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PRESS-WORKING OF 
METALS. 



A TREATISE UPON THE PRINCIPLES AND PRACTICE OF 

SHAPING METALS IN DIES BY THE ACTION OF 
PRESSES, TOGETHER WITH A DESCRIPTION 
OF THE CONSTRUCTION OF SUCH IMPLE- 
MENTS IN THEIR VARIOUS FORMS, 
AND OF THE MA TERIALS 
WORKED IN THEM. 



BY 

OBERLIN SMITH, 

Member American Society of Mechanical Engineers ; 

Member American Society of Civil Engineers ; 

Member American Institute of Mining Engineers; 

Associate Member A merican Institute of Electrical Engineers, 



Illustrates witb 433 Bugravinos. 



FIRST EDITION. 
SECOND THOUSANiy.' 



N-EW YORK: 

JOHN WILEY & SONS. 

London: CHAPMAN & HALL, Limited. 

1901. 



Copyright, 1896, 

BY 

OBERLIN SMITH. 



y / ^ & 7 

-OH 






ROBERT DRUMMOND, EI.ECTROTYPER AND PRINTER, NEW YORK. 



V 



TO 

f>rot 3. 38urfeftt Mebb, 

THE AUTHOR'S EARLY ASSOCIATE IN THOSE PRACTICAL RESEARCHES 

AND PEEPS BEHIND THE SOMETIMES RELUCTANT CURTAIN 

OF NATURE'S ARCANA WHICH HAVE LED, AMONG 

OTHER THINGS, TO THE WRITING OF ITS 

PAGES, THIS BOOK IS AFFECTIONATELY 

DEDICATED. 



PREFACE. 



Did there already exist an extensive literature upon the 
subject treated of in these pages, their somewhat meager in- 
formation might in some cases prove superfluous. Failing,, 
however, to find upon record many of the facts and principles 
which seem necessary to the successful design, construction, 
and operation of presses and dies, I have drawn upon a per- 
sonal experience of many y#ars in this line of work, and pre- 
pared a treatise which, as far as it goes, may perhaps be of 
value to the makers and users of the interesting class of tools 
which serve as its subject-matter. The use of these tools is 
very rapidly increasing in recent years, an almost marvelous 
variety of articles now being pressed out of sheet- or bar- 
metals which a few years ago were hand-forged or cast, or 
were non-existent. 

Such cut, pressed, stamped, and drawn articles are found in 
all departments of our modern civilized life, often forming in- 
tegral parts even of the cradle and the coffin — not to speak of the 
wedding-ring between. The system by which they are manufac- 
tured appears as a large factor in the creation of civilization 
itself, by making possible the cheap and uniform production 
of much of our hardware, our cooking utensils, and plate, and 
jewelry; our timepieces, and sewing-machines, and type- 
writers; our reapers, and wagons, and bicycles — to say nothing 
of the numberless other tools pertaining to our complex life, 
from a button even to a steamship. 

The number and variety of these press-begotten devices is 

5 



6 PREFA CE. 

so enormous that the maker of any one of them should but 
gently criticise my book if haply he finds not therein full in- 
struction for the production of his specialty. Many of the 
articles produced in dies, if of a difficult form, can be perfected 
only by careful, and sometimes perplexing, experimentation. 
It often takes a good while to find out into what shapes the 
Creator intended a piece of metal to flow, and what are His 
eternal limitations. The general principles governing all this 
work I have, however, attempted to set forth— at any rate to 
a hint-giving extent. 

A portion of the matter herein contained was written 
over two years ago at the request of the editor of the 
"Metal Worker" of New York, and was published as a 
serial in that journal, and also in the " Iron Age." Several 
new chapters, however, have since been introduced, together 
with over a hundred additional engravings, and the whole has 
been subjected to a careful revision and amplification. No 
attempt has been made to limit the language to the rigid 
brevity and technicality of a text-book on mathematics or 
chemistry, a freer style, rhetorically speaking, being perhaps 
more acceptable to the general reader. 



O^vdMVK SwvJch^ 



Bridgeton, N. J., 
January i, i8g( 



CONTENTS. 



CHAPTER I. 

INTRODUCTORY. 

PAGB 

Beginnings of the Art— Fundamental Principles— Probable Ori- 
gin—Rotary Operations— Press Definitions— Press Qualifications 
— Nomenclature II 

CHAPTER II. 

PRESS CLASSIFICATION AND ANATOMY. 

Classification by Motions — Classification by Position— Classifi- 
cation by Frame Design — Composite Frames — Classification by 
Method of Support— Classification by Kinetic Construction— Clas- 
sification by Power Applied — Classification by Functions — Classifi- 
cation by Materials Worked — Name Guessing — Points for a Press- 
buyer — Artistic Design — Some Power Press Problems — Clutches — 
Sub-presses ...... 20 

CHAPTER III. 

A "museum" of presses. 

Press Literature — A Pictorial Collection — Hand Presses — Foot 
Presses — Drop Presses — Power Cutting Presses — Power Double 
Crank Presses — Power Embossing Presses — Power Punching 
Presses — Power Punches and Shears — Power Curling and Horning 
Presses — Power Drawing Presses — Power Re-drawing Presses — 
Coining Presses — Hydraulic Presses — Hammering Machines . 42 

CHAPTER IV. 

DIES. 

Definitions and Evolution — Classification by Functions — Inter- 
changeability — Bolsters — Attaching Dies — Accuracy and Durabil- 

7 



CONTENTS. 

PAGE 

ity — Some Specimen Dies — Composite Die Construction — Heights 

cf Ram and Dies — Die Lubrication — Nomenclature. . . • 73 

CHAPTER V. 

MATERIALS AND MEASUREMENTS. 

Commercial Materials — Wire Gauges — A Proposed New Gauge — 
Micrometers — Annealing oj 

CHAPTER VI. 

CUTTING PROCESSES. 

Explanatory — Chiseling — Shearing — Dip or Shear — Punching — 
Deep Punching — Punching Tapering Holes — Imperfect Sheared 
Surfaces — Drifting or Repunching — A Museum of Blanks — 
Gang-cutting — Combination Cutting — Successive Cutting — Suc- 
cessive Gang-cutting — Cutting Die Qualifications — Hardness of 
Dies — Bevels of Cutting Edges — Strippers, Hold-downs, etc. — Die 
Gauges — Cutting Speeds — Cutting Pressures — Adaptation of 
Presses . 123 

CHAPTER VII. 

BENDING PROCESSES. 

Bending — Forming — Embossing — Cutting-Forming-Embossing 
— Knockouts — Speed and Pressure — Assembling — Involuntary 
Processes — Soft Punches — Fluid Punches — Presses Suitable . . 154 

CHAPTER VIII. 

CURLING AND SEAMING PROCESSES. 

Curling or Wiring — Outward Curling — Inward Curling — Assem- 
bling by Curling— Principles of Curling— Straight Curling— Horn- 
ing or Side-Seaming — Speeds and Pressures — Suitable Presses . 167 

CHAPTER IX. 

DRAWING PROCESSES. 

Drawing Historically — Drawing Defined — Mechanics of Drawing 
— Flow of Metals — Conical Drawing— Depth of Drawing — Body- 
wrinkles — Flange Wrinkles — Proportions of Work — Multiple 
Drawing — Condition of Dies — Cutting-Drawing-Embossing — 



CONTENTS. 9 

PAGE 

Specimen Drawn Work — Spring-drawing — Blank Dimensions — 
Blank Formulae — Trimming Edges — Roller Spinning — Roller Curl- 
ing — Speeds and Pressures — Kinds of Presses Desirable . . 184 

CHAPTER X. 

RE-DRAWING PROCESSES. 

Re-drawing — Inverted Re-drawing — Broaching — Vee Blank- 
holders — Rim-forming — Neck Reducing — The Speed and Pressure 
— Presses most Suitable — Drawing, Prophetically .... 214 

CHAPTER XI. 

COINING PROCESSES. 

Drop Forgings — Coining Coins — Riveting — Compressing Plas- 
tic Substances — Tube "Squirting" — Speed and Pressure — Presses 
Used 223 

CHAPTER XII. 

PRESS FEEDING. 

Definitions — Hand Feeding — Roller Feeding — Reel Feeding- 
Grip Feeding — Carriage Feeding — Dial Feeding — Friction Dials — 
Indexing — Gravity Feeding — Knockouts — Pushouts — Feeding 
Speeds — Special Automatic Machines 233 

CHAPTER XIII. 

MISCELLANEOUS. 

Manifolding Work in Dies — Paper-working — Hammer Blows — 
Effective Pressure in Drop Presses — Testing Pressures — Electric 
Driving — Power Required for Presses— Future Development . 249 

Index of Subjects — Alphabetical ....... 263 



PRESS-WORKING OF METALS. 



CHAPTER I. 
INTRODUCTORY. 

Beginnings of the Art. 

Of the origin and history of the art of metal work as 
performed in dies, operated by presses, we know but little. 
The numberless wonderful and beautiful operations of to- 
day, most of which it must be acknowledged, however, tend 
rather to cheapening and unifying than to beautifying the 
articles produced, are merely the results of a long course of 
evolution, tending constantly to a survival of the fittest 
methods. Regarding the progress of the art as a whole, it 
cannot be said that any one age shines out upon the pages 
of history, or that any one inventor has made himself im- 
mortal. Processes identical in principle with many of our 
modern ones were undoubtedly practiced by that master 
metallurgist and machinist, Tubal-Cain, and by the long line 
of skilled artificers who have been his disciples and followers 
adown through all the ages which have gradually created 
civilization. 

This civilization in its modern glory, and its far greater 
glory yet to come, may be regarded as almost wholly depend- 
ent upon the noble art of metal working in its various branches ; 
for we cannot conceive of the existence of the constructions 

ii 



12 PRESS-WORKING OF METALS. 

and instruments of modern engineering and other sciences if 
we were limited to such primitive materials as wood and stone. 

Fundamental Principles. 

In choosing the specific subject of this book, differen- 
tiating the general theme of metal-working by selecting sbeet- 
and bar-metals, and this again by limiting himself to the 
operations of a particular class of tools, the author realizes 
that he must not lose sight of certain fundamental principles 
which underlie the art as a whole; considering the important 
divisions of casting, forging and finishing, as well as press- 
working, but omitting reference to purely chemical and elec- 
trical processes. 

It may be well in this connection to say that the four 
process-defining verbs employed near the end of the last 
sentence are used in a commercial and technical sense rather 
than in a scientific one, as they somewhat overlap each other 
in exact meaning. This is readily seen when we consider that 
casting, which generally means the running of molten material 
into a mold by the force of gravity merely, sometimes also 
means the forcing of the same thereinto by means of a 
pump, or its equivalent, as in type casting and the Whitworth 
pressure system of steel casting. From this it is but a step 
to the drop-forging of white-hot iron in the dies of the drop 
press or (in other materials) to the pressing to shape of semi- 
molten glass, or of cold soap and candy. The differences 
are chiefly those of the degree of plasticity in the substance 
treated. We thus find no very distinct line of demarcation 
between casting and forging, for much of the ordinary black- 
smith's work is analogous to drop-forging, except that his 
tools are not as highly specialized, and do not so completely 
give their own form to the work. Again, we find that fin- 
ishing (in the sense here used of paring and scraping or 
abrading the surface of the metal to more accurate shape, 



IN TROD UC TOR Y. 1 3 

as in machine shop processes) is partly includea in a black- 
smith's work, as in chiseling, filing, etc. Still again, we 
shall see that press-working may, and sometimes does, in- 
clude all of the processes referred to — e.g., forcing into molds, 
as in casting; cutting, shearing, punching, smashing, bend- 
ing, stretching, compressing, etc., as in forging; and paring, 
etc., as in finishing. 

In general, however, it may be said that press-work has 
much more in common with forging than with the other pro- 
cesses in question, and that it bears the same relation to the 
blacksmith's or the coppersmith's work that printing does 
to the scrivener's art, or chromo making to oil painting, or 
a knitting machine to one's grandmother. In any of these 
cases we have on the one hand a mechanico-reproductive 
process wherein the brain of the designer has been expended 
upon specialized tools which will produce predetermined ar- 
ticles, all exactly alike, for the benefit of the millions — in 
many cases, unfortunately, with but little embodiment of 
the aesthetic. On the other hand, we have much more ex- 
pensive products, each made singly as the individual child 
of the artisan's brain, and each differing in some degree from 
its brethren. Should the artisan happen to be also an artist, 
as were the stone cutters of Greece and of mediaeval Europe, 
the gold, bronze and iron workers of old Italy and Spain 
(but as a*e not, alas! the most of our metal workers of to- 
day), then his beauty-loving individualism in mechanical 
work serves as a leaven to leaven the lump of ugliness that 
tends to crush down all love of the beautiful in this intensely 
utilitarian age. 

Referring again to certain general principles underlying 
the mechanical working of metals (at any rate, in all the pro- 
cesses mentioned except finishing), we have as one necessary 
condition a molecular structure which will enable the par- 
ticles to flow among themselves when the proper force is 



14 PRESS-WORKING OF METALS. 

applied. In the case of casting this occurs at a temperature 
at which the particular metal in question happens to become 
a perfect liquid or nearly so. In forging the flow usually 
takes place at a bright red heat, although sometimes the 
metal is cooler than this, or even entirely cold — this latter 
term meaning here (and throughout this treatise) the ordinary 
temperature of the atmosphere. In press-work the metal is 
sometimes heated as in forging, but in the great majority of 
cases it is handled cold. 

The other necessary condition, besides a capability of ap- 
proximately non-elastic flow in the material worked, is the 
employment of certain tools that will first cause this flow 
and that will then limit it, so as to produce the predeter- 
mined shapes required. In ordinary casting these tools con- 
sist of the molds to inclose and limit the shape, together with 
a proper pouring tube (wherein the sprue or gate is formed) 
to give " head " or pressure to the metal. In forging, they 
consist of the surfaces and corners of hammers and anvils, 
together with horns, swages, fullers and other more special- 
ized tools. In that modification of a forge-shop called a roll- 
ing mill, the tools in question, of course, consist of the sur- 
faces of the rolls, whether they be cylindrical to produce sheet 
metal, or grooved in various ways to produce bars. In press- 
working the forcing tools are the press rams, while the 
limiting and shaping operations are performed by the dies. 

Probable Origin. 

Before proceeding to a practical analysis of the press- 
working art as we find it existent to-day, it will be well to 
recur once more to the historical aspect of the subject, that 
we may trace its probable beginnings back in the primitive 
ages of the world's history. The first man who chanced to 
dig up a little nugget of native gold or copper, or some other 
man who found a piece of malleable metal in the ashes of 



IN TROD UC TOR Y. I 5 

his fire as a result of the accidental smelting of certain ore 
happening therein, may very probably have pounded it out 
thinner between two stones, and thus have become the first 
sheet-metal manufacturer. If he then cut it in two by lap- 
ping it over the sharp edge of a stone and sliding another 
one down past it, he had invented the first shearing press. 
If he pushed the end of a sharp-edged cylindrical stone through 
it into a hole in a stone underneath he was doing the first 
punching. If the upper tool was rounded off so as not to 
cut through, being perhaps a hard-wood stick, he was making 
a little cup by the process of forming or stamping. In the 
frontispiece a hint at such performances is attempted, but 
it is only fair to state that no photographs of the figures or 
landscape were available. 

Thus simple, however, in principle, are most of the 
operations that we still perform in sheet-metal work. We 
have improved their only in detail, gradually evolving better 
and better tools, to the end of obtaining more and more 
accuracy, uniformity and rapidity of production. The transi- 
tion from a punch or upper die, held in and guided by the 
hand, to a simple machine wherein the same was guided by 
being attached to a moving ram, was but a natural one and 
something that required no great inventive ability. The 
great economic and epoch-making advance which followed 
later was the specialization of a part of this work into certain 

Rotary Operations. 

It is evident that the action of a pair of rolls, such as are 
used in ordinary rolling mills, for reducing the thickness and 
increasing the length, and sometimes the width, of a piece 
of metal, as well as in some cases bending it to a different 
form, as, e.g., in the case of corrugating, is somewhat anal- 
ogous to the action of dies approaching each other in a press 
■ — in the processes of mashing, forming, embossing, coining,. 



1 6 PRESS-WORKING OF METALS. 

etc. The shearing action of a press also has its analogue in 
the rotary cutters mounted upon parallel shafts which are 
often used for slitting and trimming sheet-metals. All this 
rolling work is cf course but a specialized specimen of the 
general operations of forging, of which press-work is another 
specimen. 

Press Definitions. 

A general definition of the word " press," as used for the 
purposes with which we are concerned in this treatise, might 
be written as follows: A machine in which a bed or anvil is 
approached by a ram or hammer, having a reciprocating mo- 
tion in a line approximately at right angles to said bed, and 
the said ram being suitably guided in the framework of the 
machine so that it may always move in the same path. It 
will thus be seen that the two important members in any 
ordinary press are the bed and the ram, and that they are 
only a more highly specialized form of the blacksmith's 
anvil and hammer or of the still more primitive large stone 
and small stone used by the predecessors of Tubal-Cain. 

Such a generic form is shown in the pictures, Figs. I and 
2, wherein F is the frame, b the part thereof serving as a 
bed and R the ram, the views being side and top respec- 
tively. The ram is arranged with a handle at the top for 
the most primitive method of operation possible. 

Press Qualifications. 

The general essentials in such a machine are a massive 
and rigid bed with a flat and true surface upon which to fasten 
one of the dies; a rigid framework extending toward and 
surrounding the ram that it may slide, or sometimes swing, 
therein with a considerable degree of accuracy; means for 
taking up lost motion caused by original looseness of fitting 
or by subsequent wear; and a somewhat massive and rigid 



IN TROD UCTOR Y. 



17 



ram, carrying proper means for fastening and securely holding 
the other die. The surface of the ram nearest the bed is 
usually fiat and parallel thereto, although for some shearing 
work and occasionally for rough punching a ram is allowed to 
swing in the arc of a circle, usually being itself in such case 
a part of one arm of its operating lever. In the vast ma- 
jority of cases, however, a ram is of cylindrical or prismatic 
form, sliding accurately in true bearings in the frame of the 
press. These bearings should, if the machine is of correct 



L 



(<■ 




>) 




«IY 








•. 






*-• 


n 


/ 




V 






M > 




c 




i- r _; s_ n u 




\ 
\ 
\ 




b 


V_J 





\ 




Fig. r. 



Fig. 2. 



design, be of great length in proportion to the thickness of 
the ram, the oBject of thus maintaining the ram rigidly in 
its predetermined path of motion being to always bring the 
dies together with the same relation to each other, that they 
may not be injured and that the work may be uniformly 
shaped thereby. 

The causes which tend to destroy this. accuracy of motion 
are: I. The springing of the ram itself, when made too slim 
and when projecting too far out of its bearings. 2. False 
motions (sidewise) in its bearings, either by their not em- 
bracing it tight enough or by their being so short as to 
magnify by means of the leverage the slight looseness which 



lb PRESS- IVOR RING OF METALS. 

is necessary in any working bearings. 3. The springing of 
the frame out of its normal shape at points between its bed 
and the ram bearings. It may therefore be said, in general, 
that it is almost impossible to make these parts of a press 
too clumsy, and that the more metal they contain, within 
reason and consistently with the space available, the better 
they are, especially as they want not only the strength to 
keep them in position, but all the inertia possible to prevent 
vibration when acted upon by the powerful and often rapidly 
applied forces necessary to move the ram. 

Nomenclature. 

Hereafter in this treatise certain parts shown in the illus- 
trations will be uniformly referred to by the following letters: 
F for press-frame; b for the bed thereof, which is usually 
but not always a part of the same casting; R for ram ; P 
for plunger; a for axis of ram; L for lower-die; U for upper- 
die; U' for drawing-punch or inner-upper-die; M for matrix; 
K for knock-out; 5 for stripper; G for gauge; p for pressure 
between ram and bed in the line of ram's axis; / for throat, 
and M for metal or other material to be worked in the dies. 
The meaning of such of the above names as are not self- 
explanatory will be made clear further on, except perhaps 
the somewhat indefinite word " throat." This (with its de- 
rived adjective "throated") will refer to the gap or space 
containing the dies in that type of press where the main body 
of the frame extends back of the vertical axis or center-line 
of the ram, rather than at each side of it as in most " colum- 
nar " frames. " Throat " is sometimes used to express the 
distance, in inches or some other unit, from axis a back to 
frame, as shown in Figs. 11 and 13. This, however, does, 
not conflict with its meaning the whole gap when no dimen- 
sions are affixed. 

The other essential parts pertaining to presses and dies 



IN TR OD UCTOR Y. 1 9 

are so numerous that no definite system can be maintained in 
referring to them. The nomenclature herein used will follow 
conventional practice as far as is feasible, but in names with 
a number of synonyms the word which seems the most in 
accordance with common sense will be selected. A case in 
point is the ram of a press, which, called by this name, 
seems to be expressed in a short, crisp manner which almost 
explains' itself (because of its ramming functions) even to 
a layman. Other names frequently used for this member 
are slide, slide-bar, bar; mandrel, gate, head, platen, drop, 
hammer, plunger, etc. The last-named word will be herein 
used for the inside ram of double-action presses, the outside 
one being called simply a ram. 

In dealing with locations, relative positions and directions 
the simple and definite words, top, bottom, right-side, left- 
side, front, back; and up, down, right, left, forward, back- 
ward, will be respectively used- — it being understood that 
they are governed by the operator's anatomy as he faces 
the working side of the machine, which is its front. Thus 
" forward " is toward him, " right " to his right, etc. 



20 FRESS-V/GRK1NG OF METALS. 



CHAPTER II. 
PRESS CLASSIFICATION AND ANATOMY. 

Classification by Motions. 

A STRICTLY logical classification of presses seems impos- 
sible, as almost any given kind of press can be grouped by 
many different systems, some of which will inevitably interfere 
with and overlap each other. One important general distinc- 
tion is that between single and double action machines — that 
is to say, between those having a plain ram with a simple 
uniform motion, and two rams, one mside the other, with 
perhaps different amounts of motion and moving at different 
times, as is the case with the ordinary drawing press. In 
some rare cases even more than two rams are used, but ma- 
chines containing them may be justly ranked with special 
machinery, and need not be considered here. 

Classification by Position. 

Another conventional classification is by position. 
Whether a press is upright, as in Figs. I and II, or inclined, 
as in Fig. 12, or horizontal, as would be the case if Fig. 1 
was fastened with its base against a vertical wall, determines 
its " position" and perhaps one of its names. In Figs. 11 
and 12 is shown a common form of press where the frame can 
be set at any desired angle between the two extremes shown, 
by swinging, rocking or otherwise revolving it, in relation 
to its legs. Such presses are usually called " inclinable," in 
distinction from the term " inclined," in which latter case 



PRESS CLASSIFICATION AND ANATOMY. 



21 



the frame is supposed to be permanently fastened in such 
position. The object of this inclination is that work which is 



; "-;;;;::,• 






" 



r q 



U 



Fig. 3. 



Fig. 4. 



Fig 7. 



Fig. 11. 



~> 



-0_ 



s 





Fig. 8. 





Fig. 9. 



Fig. 10. 




Fig. 12. 



knocked up from the lower die, and delivered between it and 
the upper die, may slide away from said dies by the force 



22 



PRESS-WORKING OF METALS, 



of gravity, usually passing through a hole, //, indicated by 
the dotted lines, and thence descending into a proper re- 
ceptacle. 

Classification by Frame Design. 

Another classification is by the kind of frame used, of 
which there are many types. The most common among 
these is the throated frame shown in side view in Figs. I, u, 
12 and 13, where the throat measurement is counted from 




Fig. 13. 

the axis a of the ram backward to the front surface of the 
frame, as at the dimension measurement /, generally ex- 
pressed in inches. Such presses are usually cast with the 
frame in one piece. The general form is obviously that of 
a parabolic beam bent somewhat into the shape of the 
letter C- Such a beam, of course, has its ends of much less 
depth than its middle portion, according to the well-known 
laws governing the strength of beams, when so constructed as 
to put equal stress upon the material at all points in their 
lengths. The ideal outside contour for such a beam is ap- 
proximately shown by the dotted line in Figs. I and 13, 
which starts at ;// and ends at n. The parts of the frame 
exterior to this line are added at the bottom to give a flat 
base and at the top to give ram bearings, but the parts neces- 



PRESS CLASSIFICATION AND ANATOMY. 23 

saty for strength lie within said dotted line. In Figs. 3 and 
4 are shown possible cross-sections of the back part of the 
press frame in Fig. 1, cut at IV x or at y s, where the tensile 
member q is connected with the compressive member r by 
two thin webs at the sides, or one web in the middle, as the 
case may be. Figs. 3 and 4 are equally good as regards the 
normal vertical strains of the press, but Fig. 3 has the well- 
known advantage of any tubular construction in regard to 
torsional strains, and is, therefore, better for a press frame, 
as there is less chance of the ram bearings springing sidewise. 
In both figures the member q is shown much heavier than 
the member r, because the usual material, cast-iron, is sup- 
posed to be employed, and this metal has a tensile strength 
much less than its compressive. In Fig. 5 is shown a cross- 
section sometimes used, where there is evidently a consider- 
able waste of material, both in the middle, s, and at the 
back, r. In Fig. 6 another section sometimes used is shown. 
The relation of q and r is correct, but there is waste material 
at s. In some cases press frames of the general Q-shaped 
type in' question are made with the projecting bed detach- 
able, and perhaps adjustable up and down. Witness an 
ordinary horn press, where the horn really constitutes the 
bed, but is interchangeable with other horns. 

Perhaps the next most common form of press frame is 
shown in front view by Fig. 7 and in top view by Fig. 8, 
where the bed is connected to the ram bearings by two ver- 
tical posts or columns, forming a part of the same casting. 
In these figures a form often used for screw presses is shown, 
but the same general construction is more often embodied in 
much taller and narrower presses, which are frequently run 
by power and used for embossing, punching, etc., particu- 
larly in cases where there is no need for passing through a 
wide sheet of metal, as is done in throated presses. In Fig. 
13 is shown a common type of press frame with an excep- 



24 



PRESS-WORKING OF METALS. 



tionally deep throat, which is used especially for heavy 
punching and shearing work. 

It is evident that in Fig. 7 the frame F consists essentially 
of a double-ended beam forming the bed, connected to an- 
other double-ended beam across the top by the two upright 
columns, which are subjected to tensile strains mostly. Any 
shape of cross-section is, therefore, suitable for columns of 
this kind (providing the beams are stiff enough), the most 
common forms being those shown in Figs. 9 and 10. 



Composite Frames. 

Besides the numerous family of seamless press frames 
there are a variety of composite constructions in which the 
frame proper is built up of several pieces. Among these a 
common form, which may be called a pillar press, is shown 
in partial front section in Fig. 14. In this case a heavy 






Fig. 15. 



Fig. 16. 



^ — - — ______ — .__^ 



Fig. 14. 



Fig. 17. 



cross beam forming the bed, and usually also the base of the 
machine, is connected to "the cross beam at the top by two 
or more cylindrical columns or pillars, which are usually 
turned and accurately fitted to bored holes in the afore- 



TAESS CLASSIFICATION AND ANATOMY. 



25 



mentioned beams, being held securely therein by large nuts 
screwed on at the top and bottom ends thereof. This is a 
common construction in hydraulic presses, and also in ordi- 
nary power presses of very large size. No attempt has been 
made in the cut to show the ram or its driving mechanism. 
It will be noticed that the pillars of this press are subjected 
to tensile stresses only, and that it is of a convenient form 
for cheaply making these members of forged metal, which, of 
course, makes them much safer against breakage. A design 
of this kind always strikes the observer as being more archi- 





Fig. 18. 



Fig. ig. 





Fig-. 2r. 



tectural in its nature than the forms previously described, as 
we have here some of the prominent elements of a Greek 
temple — the stylobate, the columns with base and capital 
and the entablature all being clearly discernible. Its struc- 
tural principle, however, is evidently very different from the 
temple in question, the stresses upon whose columns are 
purely compressive. 



26 



PRESS-WORKING OF METALS. 



Another composite form of press frame is shown in Fig. 
21, where the columns are usually of cast metal and where 
the cross beams forming the bed and what, for want of a 
better name, we will call the head, are notched into the col- 
umns and secured therein by heavy bolts from the outside. 
The stresses upon these columns are largely tensile, but 
strongly approach lateral stresses at the points of junction 
with the cross members. 

Still another form of frame is shown in Figs. 22 and 23, 




Fig. 22. 




Fig. 23. 

where the portraits, in front and partial top views, respec- 
tively, are of a somewhat corpulent member of the genus 
drop press, the ram being shown half way up, but without 
its lifting devices. Such a method of fastening the columns 
to the bed is sometimes used in other than drop presses, but 
is not well calculated to resist tensile stresses. This feature 



pa ess classification and anatomy. 27 

is, however, of no importance in the case shown, where the 
ram falls by gravity and is not pushed downward from any 
part of the frame as an abutment. This same remark in 
regard to an upper frame not needing strength, except for 
ram guiding purposes, when gravity actuates the ram, will, 
of course, also apply to such constructions as Figs. I and 7. 
In Fig. 24 is shown one of the forms of swinging ram pre- 
viously referred to. In this way are built the well-known 
lever or alligator shears used in rolling mills, etc. The same 
principle is obviously employed in ordinary scissors, belt 
punches and other such tools. In one sense the ram may be 




Fig. 24. 



said to form the upper arm of the frame. Numerous other 
frame constructions might be described, but the instances 
given will cover the majority of those in use. 

Classification by Method of Support. 

Another classification in commercial use is founded upon 
the fact that some presses stand upon the floor, either upon 
legs attached to the frame, as in Figs. 11 and 12, or with 
a base extending downward from the frame proper and rest- 
ing upon the floor, as in Fig. 13, or in cases like Figs. 14, 
21 and 22, where the bed is thick enough up and down to 
nearly or quite reach the floor, and does not need to be ar- 
tificially raised up therefrom. 

In contradistinction to these floor presses, whose peculiar- 
ity is usually not mentioned as such, are the bench presses, 
so-called, which are often set with their bases resting upon 



28 PRESS-WORKING OF METALS. 

an ordinary work-bench, or in some cases upon one made 
lower than usual. The type of frame usually employed in 
such presses is shown in side and top views in Figs. I and 
2, and in front and top views in Figs. 7 and 8. Drop presses, 
as in Fig. 22, are often used in this way also when they 
happen to be of small size. It is obvious that press frames 
can be so mounted directly upon a bench only when the 
depth of the bed is considerably less than the usually con- 
venient height for setting the top of the press bed above the 
floor, which is generally about 32 inches. 

Obviously other classes analogous to these might be estab- 
lished, as, for instance, wall, ceiling and suspension presses. 
As a practical matter, however, the former two of these are 
rarely used. An instance of the latter is seen in the portable 
steam, pneumatic and hydraulic '" crabs " which are used 
for punching and riveting, mostly upon boiler and ship work, 
and which are usually suspended from a trolley above and 
driven through the medium of a fluid-conveying hose, or an 
electric conductor. 

Classification by Kinetic Construction. 

The next general method of classifying presses is by their 
kinetic construction, and they are often named after some 
important member of the driving mechanism, as for instance 
lever presses, screw presses, toggle presses, crank presses, etc. 
Before analyzing the kinematics of the subject more in detail 
(when, by the way, I will for convenience include drop 
presses^ considering the center of the earth as pulling the 
ram down by an imaginary cord) it will be well to look for 
a moment at Fig. 1 and consider again the primal principle 
involved in all machines of this character. I have here 
shown the simplest possible form of press which would prop- 
erly guide and strike together the two dies U and L, shown 
in dotted lines. It is, of course, but an amplification of the 



PfiESS CLASSIFICATION AND ANATOMY. 29 

round stick of the primeval savage, slid by the pressure of 
one hand through the other hand closed around it as a guide, 
and pushed down over a hole in a flat stone, as imagined in 
the early part of the last chapter. In this case the ram R 
is shown of a rectangular cross-section at v w, that it may 
not revolve and alter the relation of the dies to each other. 
It can obviously perform, within certain limits of pressure, 
all the functions of a press if the ram is simply pushed 
down by the hand of the operator. Indeed, such presses, 
with a spring added to lift the ram, are frequently seen 
upon office desks for embossing documents of various kinds. 
If it is worked upon a somewhat different principle, by the 
ram being lifted and allowed to do its work in falling, it then 
becomes a true drop press. 

In Figs. 15 to 20 are shown cross-sections of various 
rams in common use, Fig. 18 being perhaps the most popular, 
its wear and that of its bearings being easily " taken up " by 
the adjustment of a single "gib." Fig. 20 is obviously 
arranged to slide upon round columns. 

In Figs. 25 to 46 are shown, diagramatically, a series 
of rams, R, with the press frames which guide them omitted, 
and with the various driving mechanisms crudely indicated 
by mere lines, which will, however, serve to show the prin- 
ciples involved. At f are shown the lever fulcrums which 
abut upwardly within some part of the frame structure. At 5 
are shown the respective shaft bearings used in the case of 
power presses. These in Figs. 36, 37, 38 and 39 evidently 
also abut upwardly. 

Describing these diagrams: Fig. 25 shows, in side view 
section, a hand lever press; Fig. 26, a foot pendulum press; 
Fig. 27, a foot lever press; Fig. 28, a hand lever toggle 
press; Fig. 29, a foot pendulum toggle press; Fig. 30, a 
foot lever toggle»press; Fig. 31, a power crank lever press; 
Fig. 32, a power cam lever press; Fig. 33, a power crank 



3© 



PRESS-WORKING OF METALS. 




Fig. 26. 



f 




Fig. 27. 




A 



Fig. 28. 




R 




v° 



Fig. 30. 





Fig. 29. 



/ 



Fig. 31. ®^2> S 



PAESS CLASSIFICATION AND ANATOMY. 



31 



/ 

Fig. 32. 



r f 



R 



Fig. 34. 



o)VS 




Fig. 33. 



R Fig. 35. 





32 PRESS-WORKING OF METALS. 

lever toggle press; Fig. 34, a power cam lever toggle press; 
Fig. 35, a power toggle press; Fig. 36, a power crank press, 
ordinarily known simply as a power press. Fig. 37 is a front 
view of the same, with the ram at down stroke; and Fig. 38 
a front view of a power double crank (sometimes called a 
double pitman) press. These latter are often used for large 
work, where the ram needs to be very long from right to 
left, and would not very well maintain its parallelism with 
the bed were it driven down at one point only. In Fig. 39 
is shown the ram of a double-action press, driven down by 
cams working upon rollers, and a plunger, P, sliding inside 
of it, driven by a crank and pitman. Sometimes, in a nearly 
similar press, the ram is driven by cranks instead of cams, 
these being of shorter stroke than the plunger crank and set 
to move in different " time." Fig. 40 shows a hand screw 
press, with the nut n abutting upward in the press frame. 
Such presses are sometimes driven by power also, by means 
of any appropriate arrangement of reversible gearing con- 
nected with the screw. Fig. 41 shows a hand drop press, 
wherein muscular action stores up the energy developed by 
gravity rather than performs direct work, and in Fig. 42 is 
a foot drop press. In both of these cases the ram is lifted 
by a downward pull upon a cord or strap running over a 
sheave at S. In some cases such muscular action is assisted 
by a pulley at 5 being made to constantly revolve by power, 
the tightening of the cord giving sufficient friction to raise 
the ram, which, however, falls and slides the cord over the 
pulley when no downward pull occurs at the other end. In 
Fig. 43 is shown a drop press with a roller-lifter for the 
ram ; and in Fig. 44 a crank-lifter drop press. The rollers 
and crank are respectively driven by power, the rollers being 
separated when the ram is to drop, or, in the other case, 
the crank being thrown out of gear with its driving shaft. 
Fig. 45 shows a pneumatic, steam, or hydraulic press, the 



PI? ESS CLASSIFICATION AND ANATOMY. 33 

ram being driven in one or both directions by a piston in 
cylinder, C. In Fig. 46 is represented one form of a mag- 
netic press, where the ram is actuated by a solenoid, consist- 
ing of a bar of iron, S, .which is drawn into a helix, //, or its 
equivalent, when a current of electricity is passed through 
the wires w w' . 

Classification by Power Applied. 

Press nomenclature enjoys another system of classification, 
which has, perhaps, been sufficiently indicated in the last 
paragraph, consisting of the kind of power applied. Thus 
we have various members of the family christened as hand 
presses, foot presses, power presses, hydraulic presses, etc. 
It is sometimes the case, however, that a foot press is sup- 
plied with a power attachment, and that a power press is 
equipped so that it can be worked by hand, usually by fas- 
tening a crank to the fly-wheel thereof. Again, a hydraulic 
or magnetic press is really a power press, because power, 
in the conventional sense of the term as derived from a 
revolving shaft, driven by steam or otherwise, has been used 
to force the water or electricity through the pipes or wires 
connected with the press. On the other hand, a hydraulic 
press might have its water supplied by a hand pump or even 
by a device supplied with a foot treadle. 

It will thus be seen that press names are still somewhat 
indefinite when derived from power-supply conditions, as 
well as others that we have considered or are to consider. 

Classification by Functions. 

Still another classification is commonly used in the com' 
mercial baptism of the useful machine which we are studying, 
viz., that of functions. Thus we have the word press pre- 
fixed with the adjectives shearing, punching, cutting, form- 



34 PRESS-WORKING OF METALS. 

ing, bending, embossing, coining, stamping, drawing, deep- 
ening or reducing, broaching, etc., almost ad infinitum. 

These names too are often misnomers, as any one of the 
presses named will upon occasion perform more or less per- 
fectly some or all of the other functions in question. Usually, 
however, the majority of its work is as indicated by its name. 

Classification by Materials Worked. 

Whether or not the classifications which we might elect to 
use are infinite in number it matters not; the fact remains 
that there seem to be an inconveniently great quantity. I 
will, however, mention but one more, which is derived from 
the material worked upon, thus giving us such names as tin 
presses, leather presses, soap presses, pill presses, brick 
presses, etc., the last three being, perhaps, distant cousins, 
of the sheet-metal press family, although much like them in 
many points of construction, and in the employment of the 
general principle of compressing and embossing the material 
used, very much after the manner of an ordinary coining 
press. Such machines as hay, cotton, and cloth presses are 
still more distant relations, but yet show a family resemblance 
in both gait and features, so to speak. 

Name-guessing. 

From the foregoing it may be inferred that when a metal- 
worker tries to solve some of the conundrums suggested by 
this subject, by going forth to select a press from among 
the numerous kinds and sizes so freely advertised in the 
market, he will find them classified and named by their 
motions, their position, their shape of frame, their method 
of support, the kinetic principle of their driving mechanism, 
their mode of obtaining power, their functions, and the ma- 
terial worked in them. Furthermore, these distinctions are 



PXESS CLASSIFICATION AND ANATOMY. 35 

overlapped and interwoven with each other in every imagi- 
nable direction, as, for instance, when anyone of a half dozen 
distinctly classified presses may with equal facility be sold 
him for a cutting press, or where all sorts of functions may 
be performed by a power press, etc. His only recourse is 
to have a general knowledge of the whole subject. This he 
must use judiciously, in connection with the advice furnished 
him by the press-maker, so as to get a machine to suit him, 
regardless of what particular string of adjectives (as numer- 
ous, perhaps, as the Christian names of a Spanish duke) 
may be tacked on to the particular article which he will 
finally select. 

Points for a Press-buyer. 

In general, a few of the most important points to be con- 
sidered by the purchaser of a press are as follows: 1. A great 
excess of strength and rigidity, that it may not break down 
or spring unduly from its normal shape. 2. Great length 
to the ram and ample surface of the proper shape upon its 
bearings and the parts of the frame which confine and guide 
it. 3. Accuracy of workmanship, especially in regard to 
the ram and its relations to the bed. 4. Durability, as se- 
cured by ample proportions in the smaller details and by 
sufficient bearing surfaces upon all the wearing parts, to- 
gether with proper material, properly hardened where neces- 
sary. 5. All the "clumsiness" possible in the bed, ram, 
and parts adjacent thereto, to give plenty of the " anvil prin- 
ciple " ; that is to say, plenty of inertia to resist sudden blows 
without undue vibration. 6. Convenience of manipulation, 
both in operation and adjustment. 7. Ample length of ad- 
justment in the ram and other members having variable 
positions, together with plenty of die room in general. 8. 
Beauty and harmony of general design. This- latter point 
may be sneered at as of no practical consequence by some 



36 PRESS-WORKING OF METALS. 

non-esthetic Philistines whose souls are but part way civilized. 
Such men, however, must sometimes buy presses. For their 
financial benefit I will say that, in the long run, those ma- 
chines which are most artistically proportioned will, neces- 
sarily, have their materials so located in detail as to do the 
most good for the least money. They will, therefore, be 
the strongest and most durable. 

Artistic Design. 

True art in machinery, however, does not consist in imi- 
tating the facade of a Gothic cathedral upon the side of a frame 
casting; or in making it look like a grape arbor, vines, leaves, 
grapes, and all — both of whi:h I have seen done by promi- 
nent makers. Neither does it manifest itself by painting birds 
and flowers and beautiful things upon an innocent press frame 
in all the colours of an autumn forest, as, some years ago, 
used to be so much the fashion. Real art is practical, and 
it is truthful. It does not allow an iron casting to imitate a 
wood molding or a stone carving, but only, merely, to be, 
lionestly, a casting. 

This, for strength and cheapness as well as beauty, 
should be of the simplest shape possible, consistent with its 
functions and the position and direction of the stresses within 
it. It should have simple rather than complex contour lines, 
and should, as far as practicable, be made bulky and hollow 
rather than with disfiguring external strengthening ribs. 
Sharp corners should be avoided where not actually required, 
and the whole surface should have a " rounded up " appear- 
ance in general. Bosses, lugs, and other projections from 
the main body of a casting should look as if they grew out 
of it, as do the branches from a tree trunk, instead of seeming 
as if they were stuck-on afterthoughts. Forged work should 
follow the same rule, as far as is consistent with forging 



PHESS CLASSIFICATION AND ANATOMY. 17 

operations. To sum up, every member of a machine should 
appear to be what it is, without shams or imitations. 



Some Power-press Problems. 

Such of my readers as are interested in analyzing more 
closely some of the various points involved in the mechanism 
of ordinary power presses I will refer to a paper read by me 
before the American Society of Mechanical Engineers some 
years ago, entitled "Power-press Problems," which will be 
found in Vol. IX., page 161, of its " Transactions."' From 
this paper I quote a few paragraphs, as follows: 

" To the maker and user of machine-tools, which are 
often quite complicated in their construction and action, 
the machine commercially known as a ' power press ' may 
seem too simple to require any literature of its own. If the 
motions are analyzed which are required in the two general 
classes — machine-tools and presses — it will be found, in ma- 
chines of the planer type, for instance, that it is necessary 
to move either the work or the cutting tool in an accurately 
straight line to a considerable distance against a cutting press- 
ure, and in two other straight lines, both at right angles to 
this first line, and one of which has its direction adjustable to 
make an infinite number of angles with the other. For the 
necessary feeds and adjustments these motions must be in 
both directions, and in the case of the first-mentioned one 
the backward or return motion must be much faster than the 
forward motion. 

" In machines of the lathe type, in which may be included 
screw machines, milling machines, boring and drilling ma- 
chines, etc., there is frequently a similar set of motions to 
the last two described for the planer; while for the first- 
named rectilinear movement is substituted a rotary one, so 
as to produce cylindrical and conical surfaces instead of 



3 3 PRESS-WORKING OF METALS. 

planes. In both types of machines many of the motions 
must be reversible, intermittent, and variable in speed. These 
requirements, together with all the adjustments necessary, 
and the great strength and rigidity which ought to be, but 
are not always, embodied in such tools, make them pon- 
derous as well as complicated, and consequently expensive. 
This ponderosity or clumsiness for the stationary and slowly 
moving parts the writer has elsewhere advocated in writing 
of the ' anvil principle ' vs. the ' riddle principle ' when criti- 
cising the extreme flimsiness of many of the machine-tools 
in the American market. . . . 

" A power press, to a casual mechanical observer who had 
not studied it as a specialty, would seem to be far easier to 
design than the machine-tools proper, mentioned above, but 
after taking it up as a specialty his judgment would be re- 
versed, and he would find several knotty problems to keep 
him awake at night while the builder of lathes or planers 
was quietly sleeping the sleep of the just. This difference 
arises partly from the fact that power-press building is both 
.a newer and a smaller industry than the making of machine- 
tools. It has not been so fully experimented with, either in 
point of time or in regard to the number of experiments — in 
other words, these machines have not arrived at the same 
stage of development in the evolution of their race as have 
the older and more numerous tribe of lathes and planers. 

"A more important difference, however, lies in the fact 
that machine-tools are subjected to very little percussive 
action, while all the parts of a power press are constantly 
endeavoring to hammer themselves and each other to pieces. 
This is due chiefly to the fact that the work in the dies offers 
a sudden resistance to the moving parts when it is struck, 
and, incidentally, to the sudden stopping and starting of 
several heavy members of the machine while the wheel which 
drives them revolves at a constant speed. 



PRESS CLASSIFICATION AND ANATOMY. 39 

" As a consequence of these conditions one of the prob- 
lems arising is, how to fasten the parts together so that noth- 
ing will jar loose or come apart while in action. . . ." 

A study of the above-mentioned conditions, and of presses 
themselves doing actual work, will convince the knowledge- 
seeker in this field that a press is a suicidal organism which 
is constantly trying to do itself serious, if not fatal, damage. 
It naturally, therefore, requires more of the doctor's care 
than do ordinary tools, and is oftener in hospital. These 
facts should make its owner more lenient in regard to its 
periodic disabilities than is often the case in press-working 
shops, where "swearing matches" at the press-makers are 
not an uncommon event. 

Clutches. 

The most unhealthy organ, so to speak, pertaining to the 
anatomy of a power press is the automatic-stop-clutch. The 
function of this device is, at the will of the operator, to sud- 
denly make a driving connection between the constantly 
revolving fly-wheel and the temporarily stationary main shaft. 
Its further duty is to disconnect these members again auto- 
matically — usually after the shaft has made exactly one 
revolution, and when the ram has reached its up, or open, 
position. 

There are many forms of these clutches in use, some better 
than others, but it is safe to say, in general, that there are 
no perfectly good ones. 

This is because of the great difficulty of making a device 
of the kind which will meet the widely varying conditions to 
which presses are often subjected after the maker has lost 
sight of them. Among these conditions are considerable 
variations in speed, in brake adjustment, in lubrication, in 
tightness of running parts, in shaft load and ram load, in 
nature of feed and other attachments, in the resilience of the 



40 PRESS-WORKING OF METALS. 

work between the dies and of the dies themselves, etc., etc. 
These differences cause "over-running" and "under-run- 
ning" of the shaft, more or less difficulty of disconnection, 
etc., and, altogether, make a clutch more suicidal in its 
tendencies than is the press as a'whole. The most destruc- 
tive action of all is usually the instantaneous starting of the 
shaft and appurtenances from a state of rest, at their maximum 
rate of speed, instead of allowing a gradual acceleration. 
This is sometimes avoided by the use of friction clutches, 
but with these certain other difficulties are apt to appear, 
especially with non-geared, fast-running presses. 

Sub-presses. 

For various kinds of work of a small and delicate nature 
a device called a sub-press, mounted upon a press proper, 
between the bed and the ram, is in rather extensive use, 
especially for jewelry, watch- and clock-work, etc. Such a 
tool usually consists of the frame and ram of a small press, 
somewhat resembling Fig. I, page 17, or, more frequently, 
as far as its frame is concerned, a columnar type of machine 
such as is shown in Figs. 7 and 8, page 21, but usually of a 
more compact design. Its base is firmly clamped or other- 
wise secured to the bed of the main press, while the top end 
of its ram is coupled somewhat loosely to the bottom of the 
main ram. Thus the up and down motion of the latter is 
transmitted to the sub-ram, and the punch attached thereto, 
while a lateral freedom of motion is allowed which prevents 
the little ram suffering by any inaccuracies of the compara- 
tively .clumsy big one. The coupling together is usually 
done by a tee-shaped head entering a groove of like con- 
formation. 

The object of using a sub-press is twofold, the first 
reason being that the delicate and expensive little dies which. 



PA ESS CLASSIFICATION AND ANATOMY. 4 1 

it generally operates may be accurately located, and fastened 
once for ail in a machine which will maintain their alignment 
better than can be done with frequent resettings, and with 
the springiness and lost motion, due to a large press whose 
ram is at a considerable distance above its bed, and which, 
moreover, has not as a usual thing the near together columns 
and closely fitted ram easily attainable upon the sub-press. 

The second reason referred to is the general convenience, 
and adaptability for quick setting, incident to a device which 
keeps its dies always ready set in relation to each other, and 
which needs but to be roughly attached to a big press that 
does not have to be kept in such transcendentally good order 
as would otherwise be necessary. The type of press employed 
for this work may vary considerably, but should usually 
comprise a rather short stroke, and a considerable height 
between bed and ram, together with a delicate down adjust- 
ment of the latter. Great accuracy of ram fit, etc., as be- 
fore intimated, is not essential, this being provided for in 
the simple, but highly organized, little sub-machines, each of 
which belongs, for the time being, to its own pair of dies 
alone. 



42 PRESS-WORKING OF METALS. 



CHAPTER III. 
A "MUSEUM" OF PRESSES. 

Press Literature. 

As far as the writer knows, the literature of this subject, 
outside of press-makers' catalogues, is extremely limited. It 
is, however, to be hoped that in the not too far off future 
somebody will give to the world a comprehensive biography 
of a family of machines which are far too useful to remain 
much longer in the realms of literary oblivion. 

In commencing this treatise there was no intention of 
making it a natural history of the press family, although it 
has seemed necessary to treat the different varieties some- 
what in detail in order that subsequent descriptions of dies, 
together with the materials worked in them and the operations 
thereupon, may be clearly understood. Were it a thorough- 
going treatise upon the machines in question, it might well of 
itself occupy a bulky volume, which should properly include 
several hundred portraits in perspective of the various types 
of these interesting tools. There might seem to be, how- 
ever, another reason besides lack of space for omitting such 
a set of pictures, viz., because it would be difficult to so 
limn them as not to make apparent some of the designs of 
well-known makers which are in the market, and thus lead 
to a suspicion of invidious distinctions, unless indeed it were 
possible to take composite photographs of all the good 
presses of each particular kind. 

This somewhat sentimental view of the case would, how' 
ever, keep all the good actual presses, with their time-proved 



A "MUSEUM" OF PRESSES. 43 

virtues, entirely out of sight, and would limit the pictorial 
literature of the subject to figments of the imagination, so 
to speak. There is therefore shown in the illustrated pages 
of this chapter a number of groups of characteristic presses, 
each group representing an important type, but not, of course, 
attempting to show a complete list of all possible varieties. 

A Pictorial Collection. 

The majority of the pictures in question are taken, by 
permission, from the catalogues of eight or nine leading 
American press-makers, two or three makers in England, and 
one or two in Germany. The English pictures are marked 
" E," the German " G," and the remainder, which are left 
unmarked, are American. No other European pictures hap- 
pened to be available, but they would not vary much from 
those shown. 

It will be noticed that some of the foreign designs shown 
resemble closely certain of the American ones. In some 
cases this is due to foreign makers having imitated something 
which they found in this country; indeed, the writer knew of 
a case where one of his own machines, of a new and unique 
design, was absolutely reproduced abroad. Such copying 
obviously cannot be prevented without having comprehen- 
sive foreign patents, but in the absence of these it is of course 
perfectly legal and may be considered in the light of a com- 
pliment to the designer. 

To balance alleged grievances of this kind, where Ameri- 
cans are sometimes apt to grumble at their ideas being 
appropriated, we must remember that very much of our 
American machinery is directly descended from European 
models, although perhaps in some cases considerable revision 
and improvement has been made. 

The pictures shown upon the various pages in this chapter 



44 PRESS-WORKING OF METALS. 

do not in all cases give a sample from each of the makers 
above mentioned in any given group, although most of the 
pages contain a considerable variety of different people's 
designs. The individual presses in each group have been 
selected as best representing a general type, with all the 
minor variations possible, so that a comparison can be made 
between several perhaps equally good methods. The no- 
menclature used is as unsystematic as might be expected 
from the explanations in the previous chapter, being some- 
times derived from the anatomy, sometimes the functions, 
and sometimes other circumstances connected with the ma- 
chine in question. On the whole, however, it adapts itself 
as nearly as possible to the popular names commercially 
used in the engineering world. Just what such a collection 
of machines as the one in question should be called in the 
ao-oreeate is a question to be considered. In lieu of a better 
name perhaps the title of this chapter, "A Museum of 
Presses," may answer as well as anything available. In view 
of the variety of families shown and the variations among 
their individual members, it is probably a sufficiently sug- 
gestive one. 

These press portraits are drawn to an approximate scale 
of |- inch to the foot, and are therefore about ^ of real size. 

Hand Presses. 

On page 45 are shown a number of presses worked by the 
hand of the operator, Figs. 47 to 49 having the common 
feature of being throated screw presses standing upon the 
floor, but Fig. 48 being different from the others in having 
the frame inclinable upon its legs, the handle adjustable 
around the screw, and the screw incased. Fig. 49 is arranged 
as what is called a sprue-cutter, having mounted in it chisel- 
like upper and lower dies for cutting "sprues" off from 
castings. 



A "MUSEUM" OF P.RESSES. 



45 




Fig. 47. 





Fig. 48. 



Fig. 49. 




Fig. 50. 




Fig. 51. 



Fig. 52. E 




Fig. 53. 




Fig. .56. 




Fig. 54. G 




Fig. 57. 




Fig. 55. £ 




4-6 PRESS-WORKING OF METALS. 

Figs. 50 to 52 show columnar screw presses, the first 
mentioned being sometimes called an arch press, from the 
general shape of its frame. 

Figs. 53 and 54. show throated bench screw presses, the 
first mentioned being provided with a stay-rod, one or two 
of which members are often added to any sort of a throated 
press to make it approximately resemble a columnar press 
in point of stiffness. 

Figs. 55 and 56 show throated portable screw presses, 
such as are usually employed for punching boiler sheets, etc., 
which cannot easily be moved to a stationary press. 

Figs. 57 and 58 show hand-lever presses arranged for 
punching and shearing respectively. In the former the lever 
has been removed from its socket and does not appear in 
the picture. Such machines were formerly more extensively 
used than now, in this day of hydraulic pipes and electric 
wires. 

Foot Presses. 

On page 47 are shown in Figs. 59 and 60 inclinable lever 
foot presses by different makers, both of which happen to 
be mounted with bolsters equipped with special die-clamps 
for quickly gripping the lower die. 

Fig. 61 shows an upright lever foot press which might be 
considered either of the bench or floor type, according to 
whether the wooden table is really counted as a part of the 
machine. 

Fig. 62 shows a lever foot press with adjustable bed, and 
with its frame extending down in the form of a pedestal to 
the floor. Fig. 63 represents a pendulum foot press with 
removable pedestal, so that it can be arranged as a bench 
press. 

Fig. 64 shows a lever bench press of small size, and Figs. 



A "MUSEUM" OF PRESSES. 



47 





Fig. 59. 




Fig. 60. 



Fig. 61. G 






Fig. 62. 



Fig. 03. 



Fig. 64. 





Fig. 65. 



Fig. 66. 




Fig. 67. G 



48 PRESS-WORKING OF METALS. 

65 and 66 pendulum presses, the latter being mounted as a 
bench press. 

Fig. 67 pictures a lever " squaring-shear " which, although 
not usually termed a press, is as much so in reality as are 
many others which happen to be provided with shearing rather 
than punching tools. 

The term pendulum is generally used, instead of the word 
lever, which it might logically be called, to designate the main 
operating lever of a press which extends direct to the pedal, 
rather than being connected therewith by a pitman and a sepa- 
rate treadle-lever, as in the so-called lever presses. 

Drop Presses. 

On page 49 is shown in Fig. 68 a hand or foot bench 
drop press, where the hammer is lifted by muscular power 
applied by the hand or foot in the respective stirrups attached 
to the rope. 

In Fig. 69 is shown a much larger machine, where a 
revolving pulley at the top gives sufficient friction to raise 
the hammer when the free end of the belt is tightened by 
the hand of the operator, which follows its motion as it 
descends. 

In Fig. 70 is shown a portable crank " lifter " for lifting 
and suddenly letting go of the hammer in almost any drop 
press, such as, for instance, in Fig. 72 or J$. 

In Fig. 71 is shown a large drop press with its ram lifted 
by rollers pinching a board attached thereto. Fig. 72 illus- 
trates another columnar, and Fig. 73 a throated, drop press, 
either of which might have its ram lifted by the same kind 
of rollers, or otherwise, as desired. It will be noticed that 
the last-mentioned machine is equipped with a dovetailed 
die chuck, while most of the others hold the lower die with 
set screws in lugs projecting up from the bed. These are 



A "MUSEUM" OF PRESSES. 



49 





Fig. 70. 





Fig. 71 



Fig. 73. 



50 PRESS-WORKING OF METALS. 

technically called " poppets." The upper die is usually 
dovetailed into the ram ; or, if of soft metal, it is held by 
casting it into . or onto some undercut recess or projection of 
proper shape. 

In Fig. 146 (at the end of this chapter) is shown a large 
steam drop press, which might or might not have the force 
of gravity augmented by allowing steam to enter the top of 
the cylinder, as well as the bottom. Its principal function, 
however, is to merely lift the ram. This much resembles a 
regular steam hammer in general design, and has been sep- 
arated from its fellow drop presses that it may appear with 
the other members of its fluid-operated family. 

Power Cutting Presses. 

On page 5 1 are shown in Figs. 74 to 82 a number of 
throated so-called cutting presses, their chief characteristics 
being that they are of a type which is considerably spread 
out, as it were, in lateral directions, so as to take large dies 
and give room for large bed-holes. They are chiefly used for 
" blanking," and are generally built lighter in proportion to 
their extreme dimensions than are some other types of ma- 
chine intended for heavier work. 

Without describing these in detail it may be remarked 
that the collection is somewhat unique, as showing no less 
than nine distinct methods of inclining the frame upon the 
legs. All of these but one have the common fault of re- 
quiring a different length of belt for different degrees of in- 
clination. This one is Fig. 78, which, on the other hand, 
has the disadvantage of requiring much more metal in the 
legs, on account of their extra height, than do the others. 
It is, however, a convenient machine. 

It will be noticed that the axis of oscillation in some of 
these presses is a considerable distance back of the ram axis, 



A "MUSEUM" OF PRESSES. 



51 




Fig. 74. 



Fig. 75. 



Fig. 7C. E 





Fig. 78. 



Fig. 79. G 






Fig. 82. 



52 PRESS-WORKING OF METALS. 

which causes the front of the bed to rise unduly when it is 
inclined. The further forward this swinging point can be 
placed, within reason, the more convenient is the height for 
the operator. 

Power Double-crank Presses. 

On page 53 are shown in Figs. 83, 84, and 85 various 
designs of so-called double-crank presses which will at a 
glance explain themselves. It will be noticed that two of 
these are what are technically termed " geared " presses, in 
contradistinction to the " non-geared " kind, which constitute 
the majority of the press family. The difference consists in 
interposing a train of gearing (usually a small driving and 
a large driven cog-wheel) between the fly-wheel shaft and the 
main shaft, instead of mounting the fly-wheei upon the latter 
shaft direct. The machines here shown are sometimes func- 
tionally designated stamping presses, to distinguish them 
from smaller types of cutting presses which have but a single 
crank and pitman. They are sometimes also called double- 
pitman presses. The ram adjustment is usually arranged 
with some coupling of the pitmans, that they may lengthen 
and shorten in unison. 

Fig. 86 shows a "twin" press, which is really nothing 
but two machines mounted upon a common table and set of 
legs, although its appearance is that of one machine, some- 
what resembling the ones referred to in the paragraph above. 

In Fig. 87 is shown a power squaring-shear very similar 
to the one operated by foot-treadle before referred to, but 
in its general kinetic construction strongly resembling the 
double-crank presses which appear above. 

In Fig. 88 is shown an entirely different form of double 
machine where each individual twin approaches toward or 
recedes from his fellow, so as to shear off both ends of the 
work at once to a predetermined length. 



A "MUSEUM" OE PRESSES. 



-j3 




Fig. 87. 



Fig. S3. E 



54 press-working of metals, 

Power Embossing Presses. 

On page 55, in Figs. 89, 90, 91 and 92, is shown an or- 
dinary type of columnar embossing press, being so called on 
account of their unusual rigidity and strength, in comparison 
to their size. This does not mean, however, a limitation to 
the function of embossing, but only that these machines are 
specially adapted for such work. The principal variations 
from the common type in the group mentioned are the 
wedge ram adjustment in the case of Fig. 89, and the eccen- 
tric ram adjustment in Fig. 92. The last named, it will be 
noticed, is a geared press, while the others have the fly- 
wheel upon the main shaft. 

In Figs. 93 and 94 are shown embossing presses of a more 
powerful type, having the ram driven up from the bottom by 
toggles. One of these is double-geared, as it is termed — 
that is, there are two pairs of gears and an intermediate shaft 
embodied. 

Power Punching Presses. 

On page 56, in Figs. 95 to 97, are shown different makes 
of the ordinary type of punching press, so called, with the 
fly-wheel at the back, and with a bed-hole large enough to 
allow for other work than the mere punching of rivet-holes 
and such. It will be noticed that the ram adjustment, 
clutches, etc., vary considerably in these machines, as they 
do in many others yet to be set forth. There is scarcely, 
however, an opportunity to here describe these devices in 
detail. 

In Figs. 98 to 100 are shown machines intended for small- 
diameter punching only, the latter being geared, and also 
being arranged so that it can be run by hand as well as power. 
The little machine pictured in Fig. 99, unlike the others, is a 



A "MUSEUM" OF PRESSES. 



55 





IMG. 91. G 








Fig. 03. 



Fig. 



94. 



5° 



PRESS-WORKING OF METALS. 





Fig. 95. 



Fig. 96. 





Fig. 97. E 



Fig. 98. 





tiG. 99. 



Fig. 100. E 



A "MUSEUM" OF PRESSES. 57 

bench press, of a type often used for making buttons, steel 
pens, and such work. 

Power Punches and Shears. 

On page 58 Figs. 101 to 106 show a variety of differ- 
ent makes of punching and shearing machines of the well- 
known type used in boiler and ship-building shops, etc. It 
will be noticed that these are all powerfully geared, and that 
some of them are twin, or double, machines, being arranged 
to punch at one end and shear at the other. In the case 
of Figs. 105 and 106, both of which happen to be of foreign 
construction, it will be observed that the ram is arranged to 
punch at one end and shear at the other so as to do work 
while running in both directions instead of only one, as in 
more common forms. 

Fig. 107, page 59, illustrates a machine which is really, as 
far as its functions go, more like those mentioned as " punch- 
ing presses," save that it is started and stopped with a hand- 
lever instead of a foot-treadle, and is not so near the average 
of conventional design. 

In Fig. 108 is shown a double machine with the rams 
sliding in an inclined position and arranged with special shear- 
blades for cutting angle-iron. This happens to be provided 
with an engine mounted directly upon it instead of being 
driven by belts, as is the case with the other machines on the 
same page. 

Fig. 109 shows a peculiar type of machine used for scarfing 
or beveling the edges of boiler plates, etc., wherein the ram 
is inclined somewhat from a vertical position, while the bed 
remains horizontal. 

Fig. no represents a heavy punching press of the hori- 
zontal type, the ram being in a recumbent position, so to 
speak, rather than upright as usual. 

In Fig. 1 1 1 is shown a heavy punching machine having 



53 



PRESS-WORKING OF METALS. 





Fig. ior. 



Fig. 102. 





Fig. 104. E 





Fig. 105. G 



Fig. 106. E 



A "MUSEUM" OF PRESSES. 



59 




---":: ,„x 



Fig. 109. 



Fig. 1 10. 





Fig. hi. 



Fig. 112. 



60 PRESS-WORKING OF METALS. 

its ram driven through the medium of a lever rather than 
direct from the main shaft, as with most of the others. 

Fig. 112 shows what is popularly known as an alligator 
shear, obviously so named from its resemblance to that long- 
bodied, strong-jawed animal. In this machine is shown an 
instance, referred to in an earlier chapter, where the ram of 
the machine swings upon an axis instead of sliding, and 
where it really serves to form a part of the main framework. 

The name " punches," as applied to many of the above 
machines, is a commercial one and is somewhat of a mis- 
nomer, as the little pieces of steel forming the upper dies 
are also called punches. This confusion of terms can hardly 
perhaps be avoided at present, until that hoped-for time 
when the mechanical world shall be blessed with some good 
dictionary-making. The machines really should be called 
" presses," just as much as should any of those we are con- 
sidering. 

One special feature noticeable in these heavy punches and 
shears is the usual (although not universal) absence of the 
automatic-stop-clutch so generally used in other types of 
power presses. In many of them an ordinary clutch, which 
can be thrown in or out of gear at almost any point of the 
up or down stroke, is operated by a hand- or foot-lever. In 
others, especially in England, the "gag" system is used. 
In these the main shaft runs all the time, and the ram nor- 
mally stays in up position, except when made to descend 
by the pushing in beneath the crank-pin box of the so-called 
gag, which is a wedge-like or other block of suitable shape, 
usually operated by a hand-lever. 

Power Curling and Horning Presses. 

On page 61, in Figs. 113 and 114, are shown different 
makes of adjustable-bed presses which are, as arranged in the 
pictures, equipped for curling or wiring thin sheet-metals, 



A "MUSEUM" OF PRESSES. 



61 





Fig. 113. 



Fig. 114. 





Fig. 115. E 



Fig. ii6. E 





Fig. 117. 



Fig. 118. 



62 PRESS-WORKING OF METALS. 

but which can, by the lowering or removal of the bed' and 
the insertion of a horn in the large hole shown above the 
same, be quickly converted into horning presses. 

In Fig. 115 is shown a curling press with the bed non- 
adjustable, with no provision for horning and cutting work, 
etc. 

In Fig. 116 is shown, per contra, a horning press pure 
and simple, having no provision for curling or other work. 

Fig. 117 shows a press arranged for horning which can, 
by the removal of the horn-carrying bolster, and the reinser- 
tion of the loose portion of the bed, shown on the floor 
removed from the front thereof, be converted into an ordi- 
nary cutting press. 

Fig. 118 shows a large horning press of a type used for 
punching and riveting small boiler shells and similar hollow 
cylindrical work. Such machines usually have the upper 
arm of the frame, which carries the shaft and ram, strongly 
braced from the main body of the frame. The lower arm, 
forming the hornlike bed, cannot be so braced, as it must 
receive over its whole length the shell to be worked. It 
must therefore be made of the stiffest material available, and 
then be allowed to spring what it will. 

Power Drawing Presses. 

On page 63, Figs. 119 to 124, are shown six different 
makes of large geared power drawing presses, three of them 
of foreign construction. They are of the usual type, with 
a plunger moving separately inside of the ram, this plunger 
in all these cases being driven by cranks or eccentrics upon 
the main shaft. It will be noticed that in Fig. 119 the ram 
is driven and held in its " dwelling " position by a system of 
toggles rather than by cams, as is the case with all the 
others of this group. Certain interesting variations in the 



A "MUSEUM" OF PRESSES. 



63 




Fig. 123. G 



Yig. 124. E 



64 PRESS-WORKING OF METALS. 

ram and plunger motions may, however, be observed. In 
Figs. 119, 120, and 122 the ram and plunger both do their 
work while moving downward from above. In Fig. 121 the 
effective stroke is upward for both ram and plunger, while 
in Figs. 123 and 124 the ram moves upward, while the 
plunger comes down to meet it. The last-named machine 
is of a design that has been built in America as well as Eng- 
land, but I am not sure as to which country originally gave 
it birth. Fig. 122 pictures a press so big that it has to be 
partly sunk in a pit. It is surrounded by its own good 
works, in the shape of a number of milk-pans that it has 
drawn from flat blanks. 

On page 65 Figs. 125 and 126 show inclinable, non-geared, 
double-action drawing presses, the frames being both throated 
and adjustable upon their legs. 

Fig. 127 shows the same sort of a machine without the 
inclinable feature, and Fig. 128 something nearly similar, but 
set permanently inclined and provided with an embossing at- 
tachment. This is of similar design to a certain American 
press, and one was probably copied from the other. Another 
feature in the latter machine, different from the others, is the 
positive lifting of the ram by means of the cams, while two 
of the others have spring-lifted rams, or a combination of 
a spring and plunger lift. The first mentioned of all has a 
toggle-actuated ram. Ram lifting upon large presses of 
this sort is sometimes performed by special auxiliary cams 
and levers. In other cases it is done by counterbalance 
weights, and in still others by the piston of a steam cylinder. 

Power Re-drawing Presses. 

On page 66 are shown, in Figs. 129 to 133, several char- 
acteristic specimens of geared " re-drawing " or " reducing " 
presses, whose chief peculiarity is an extra long stroke, their 



A "MUSEUM" OF PRESSES. 



^ 





Fig. 126. 




Fig. 127. G 




Fig. 128. E 



66 



PRESS-WORKING OF METALS. 





Fig. 129. 



Fig. 130. 





Fig. 131. 



Fig. 132. G 




Fig. 133. 



A "MUSEUM" OF PRESSES. 6? 

motion being single-action. Their function is usually the 
" re-drawing," or reducing," or " deepening," or " broach- 
ing," or " drawing," as the operations are variously termed, 
of " cups " which have been made from flat blanks of sheet- 
metal in double-action drawing presses proper, as before de- 
scribed. Obviously their functions need not be limited to 
work of this sort, however. In Fig. 131 the ram has a vari- 
able stroke of considerably greater amplitude than usual, and 
is operated by a rack and gearing rather than by a crank, 
as in most of the other ones. The press in Fig. 132 is of 
the power screw type, having the unique feature (in this 
country at least) of a screw-actuated ram, where a friction 
wheel mounted upon the top of the screw is driven by the 
adjustable friction disks upon the horizontal main shaft, the 
motion downward being, obviously, an accelerated one. 
These machines are used in France and Germany to a con- 
siderable extent (and for a variety of purposes), but not much, 
as yet, in this country. Fig. 133 pictures a horizontal re- 
drawing press with an automatic feeding attachment, such 
as is used for reducing and deepening cartridge shells, etc. 

Coining Presses. 

On page 68 is shown in Fig. 134 an ancient coining press 
of unknown date. For the representation of this and the 
next picture I am indebted to the kindness of Mr. Evans of 
Philadelphia, who published them some time ago in a book 
describing the Mints of the United States. The lower arm, 
forming the bed, and the upper arm, serving as the ram, 
were evidently intended to be brought together by being 
placed between an anvil and a hammer. Its crude form 
and cruder method of operation, together with its roughly 
coined products, speak clearly for themselves. 

On the same page, in Figs. 135 to 138, are shown auto- 



68 



PRESS-WORKING OF METALS. 




Fig. 137. 



Fig. 138. 



A "MUSEUM" OF PRESSES. 69 

matic coining presses with tube feeds, such as are used in 
the mints of the United States and elsewhere. The last- 
mentioned one has the ram driven from below, but all of them 
are operated by powerful toggles, and are provided with a 
tube in which the blanks, or " planchets," for the coins are 
placed, the same descending by gravity until pushed in by 
feeding " fingers to a position between the dies. Provision 
is of course made for automatically ejecting the coin from 
the ring into which it is expanded, and for pushing it laterally 
away from the machine. Fig. 136 is an English design. 

Hydraulic Presses. 

On the upper part of page 70, in Figs. 139 and 140, are 
shown respectively a throated and a columnar hydraulic 
press, the latter being provided with pumping apparatus as 
an attachment thereof. Such a machine is sometimes used 
for the heavy coining of medals, etc. ; although, as is well 
known, its additional functions are almost infinite in number, 
in regard to metal-work and for other purposes. The first- 
named press is shown equipped for ordinary punching work. 

In Fig. 141 is shown a horizontal hydraulic press such 
as is used for deepening rather large cartridge shells and 
other similar work. All these liquid-driven machines are 
very powerful, but comparatively slow in their action. 

In Fig. 142 is shown a horizontal hydraulic press wherein 
the ram is mounted at the top of a high arm, forming a part 
of the frame, with the bed serving as an abutment and form- 
ing another arm, also projecting upward to the same height. 
The function of such a machine is usually the punching and 
riveting of steam-boiler shells at a considerable distance from 
the ends thereof, one wall of the shell being slipped down 
between the arms mentioned. 



;o 



PRESS-WORKING OF METALS. 




Fig. 139. 



Fig. 141. 





Fig. 143. 



Fig. 144. E 



Fig. 145. 



A " MUSEUM" OF PRESSES. 



n 



Hammering Machines. 

In Fig. 143 is shown a throated-frame gas hammer, which 
may be considered as a closely related cousin of the steam- 
hammer family. The chief differences in construction are 
due to the requirements of gas rather than steam as the driv- 
ing fluid. Although it may be objected that a hammer is 
not, strictly speaking, a press, and therefore that it does 
not belong in this collection, there is really no essential differ- 
ence in the motif of these two machines. 

In Fig. 144 is shown a small steam hammer with the 
throated style of frame usually employed upon small and 
medium sizes. The columnar style used for very large ham- 
mers is represented in Fig. 146, as applied to a big steam 




Fig. 146. 

drop press. This is nearly like a hammer in general style 
and has been further described under the head of drop presses 
on page 50. 



72 PRESS-WORKING OF METALS. 

In Fig. 145 is shown what is termed a power hammer, the 
ram of which is actuated by a crank, very much in the same 
way as in an ordinary press, except that there is an elastic 
spring connection in the pitman between, thus not making 
the ram's motion positive in relation to the crank, and giving 
a quicker and more hammerlike blow. This has an action 
much like that of a steam hammer and is used for the same 
general work, chiefly forging. Hence its place in this part 
of the chapter. 



DIES. 71 



CHAPTER IV. , 

DIES. 

Definition and Evolution. 

HAVING in the previous chapters attempted to define, 
briefly describe, and to some extent classify presses of various 
kinds, it will now be in order to describe the tools comple- 
mentary thereto, which are commonly known as dies. Such 
dies, considering any one unit of their quantity, may be de- 
fined in a general way as: a pair of special tools so related 
.to one another that when properly guided and approached 
toward each other, with sufficient pressure, they will produce 
a definite, uniform, and permanent change upon each one of 
certain similar pieces of suitable material placed between 

them. 

The history of dies is doubtless hidden still farther back 
in the dim obscurity of the long ago than is that of the 
primeval presses referred to in the first chapter. A begin- 
ning of putting the die-using principle into practice was made 
when Adam sewed together his fig leaves — that is, if, as seems 
rather probable, he punched holes in them with a big thorn, 
letting it penetrate the leaf and enter the space between his 
fingers beneath as it lay flat upon his hand. A pair of fingers 
and a thorn were thus an analogue of early punching dies, 
these tools, like more modern dies, being capable of pro- 
ducing "duplicate work" upon a great number of pieces. 
After the same fashion we may trace the action of forming 
dies in the corrugating of a leaf or a piece of bark placed 



74 PRESS-WORKING OF METALS. 

between the hands, with the fingers of one partly entering 
the inter-finger spaces of the other. When a lump of clay 
or a snowball (if snowballs were climatically practicable in 
primeval times and places) was firmly grasped between the 
two intaglios of a pair of hands the resulting double-faced 
cameo, with its reversed finger contours, and its " lines" of 
" heart," of " fortune," and of " fate," as the palmist calls 
them, was a product of an early style of coining dies — as 
truly, indeed, as is a " pat " of butter the product of a later 
style. 

We have no record of the actual beginnings of metal- 
working dies, but we know that at a period some seven cen- 
turies before the Christian era the Greeks made rather good 
coins and medals with tools of this kind. The manner of 
their gradual development from the crude hints given by 
the finger-compressed ball of clay must forever be left to 
the imagination only. A curious thing in history is the 
fact that the art of printing, which is only in reality a special- 
ized form of die-work, plus the inking, should have been 
perfected but so recently. Perhaps this is merely because 
the world was not earlier ready for it. 

The construction of some of the commoner forms of metal- 
working dies would seem not to have been blessed with much 
improvement during the last two thousand years or so, ex- 
cept perhaps in accuracy of dimension and shape. There 
have been, however, especially in the present century, many 
new processes invented, for which special dies have been 
contrived — particularly combination and gang dies of various 
kinds. Much has of course been gained in the way of elabo- 
ration of detail upon finely engraved surfaces, etc., since 
the microscope has been available as an instrument of pre- 
cision. 

In the methods of making dies wonderful improvements 
have been developed in modern times, chiefly in the way 



DIES. 7 b 

of cheapening and increasing the efficiency of die-makers' 
tools. 

The operating of all sorts and conditions of dies has ob- 
viously been enormously cheapened and improved by means 
of the presses considered in the preceding chapters. 

Classification by Functions. 

Like presses, dies are somewhat difficult to classify, but 
not to so great a degree. It will here be sufficient to classify 
according to their functional character only, without attempt- 
ing to do so by the material they are made of, by the kind of 
press they are fitted to, by their method of construction, 
or any other of a dozen systems that might be contrived. 
In each class, as, for instance, cutting dies, there will be 
necessarily a number of varieties, based somewhat upon the 
material to be worked and the condition in which it is to be 
put. No attempt will be made at a disquisition upon the art 
of die-making, as such might well occupy a complete vol- 
ume in itself. The chief purpose of these chapters is to 
describe the operations practiced by the metal-worker as 
he views them from his standpoint, or, rather, as he should 
view them. In carrying out this idea it has been necessary 
to refer to the different forms of presses, without going into 
the details of their mechanical design. Dies will be herein 
treated the same way, only such details of their construction 
being given as are necessary to illustrate their action, both in 
theory and practice. In describing each general class some 
advice may be given as to certain good points in these tools 
which should be looked after by their users, but the methods 
of manufacturing them and their exact design, as far as con- 
cerns the best modes of putting together, etc., will be left to 
the unknown makers thereof. 



76 PRESS-WORKING OF METALS. 

INTERCHANGEABILITY. 

While speaking of dies in a general way, and before en- 
tirely leaving the subject of variations in presses, it will be 
well to show by illustrations a few of the most common 
methods of fastening dies to the beds and rams, respectively, 
of the presses in which they are to be used. Some of these 
varying methods are equally good, but an important point 
with the user of .such tools is to arrange for interchangeability 
to the greatest possible extent — not only that certain given 
dies may fit as many presses as possible, as far as the kind 
and size thereof will permit, but especially that the numerous 
dies which he very probably has on his shelves (either 
actually or in prospect) may, as far as can be, fit in common 
a given press. Too much importance cannot be attached to 
the attainment of a strict system of uniformity in these fas- 
tenings, so that certain dies can be quickly taken out of a press 
and others substituted, and also that there may be as few 
changes as possible in the adjustments of the press itself. 

Bolsters. 

In Fig. 147 is shown, in vertical axial cross-section, a 
bolster, B, on which is fastened by tap-bolts screwed into 
the same a lower die, L, it being understood that this bol- 
ster is, as usual, simply a flat plate bolted or otherwise se- 
cured to the bed of the press to which it belongs, in the 
customary way, such bolsters being generally furnished by 
the press-makers either as a standard part thereof or especially 
to order. They often have a hole of some size and shape 
through them, as in Fig. 147, but are sometimes solid, as in 
Figs. 148 and 154. The bolster, i?, Fig. 148, is shown with a 
truss or boss, z, projecting below its bottom surface and ex- 
tending downward into the bed of the press. Such trussed 



DIES. 



77 



bolsters are often useful for heavy work that happens to be 
concentrated near the center. 

The general object of a bolster is to occupy some of the 
spare room, up and down, which is usually allowed in case 
extra high dies should be required for some special purpose; 
and also to partly cover up and bridge over the large hole 
which is generally made through a press-bed, that work of 
a maximum size may sometimes be dropped through. Both 
of these objects are obviously to enable smaller and cheaper 
lower dies to be used for average work than would be the 
case were each die required to be thick enough and to have 
its flange ©r plate spread out far enough to reach the bed- 
bolts of the press which usually secure the bolster. 

Attaching Dies. 

In Fig. 147 R represents the lower part of a press ram, 
in which is inserted the upper die U, it being shown in this 




Fig. 147. 
case with a tapering shank, S. This drives tightly into the 
socket of said ram and is prevented from slipping out by a 



78 



PRESS-WORKING OF METALS. 



set-screw, which, for better security, is usually made with a 
point, countersunk into the shank. To save complication 
these dies are shown perfectly flat upon the faces which come 
together, and in this shape may be regarded as flattening 
dies, such as are frequently used for straightening and com- 
pressing small articles. Almost any variety of dies can ob- 
viously be secured by this and the other methods to be de- 
scribed. 

Fig. 148 shows shank of die U cylindrical instead of 
conical. In this case the set-screw does not need, neces- 

B 



nJl 




Pig. 148. 

sarily, to be countersunk therein. The top end of shank x 
is shown as having a bearing against top of ram-hole, as well 
as the top surface of the die proper at y having its bearing 
upon the bottom of the ram, it being better in all cases to 
have as much contact of solid metal as possible, to carry the 
heavy compressive stresses incident to all work of this kind. 
In the same picture the lower die L is shown fastened by 
tail-clamps, C C, the latter being of a crude form often 
used, where a piece of bar-iron is simply bent at right angles 



DIES. 



79 



and a bolt-hole is thrown at it, so to speak, almost anywhere, 
instead of being put as close to the die as possible. Such 
a construction not only enables the clamp to bend down, but 
loses a good deal of the leverage that may be gained by ar- 
ranging the proportions as in clamp C, where the bolt is 
put near the die. This clamp is of better design for with- 
standing bending-strains, being thickened at the bolt-hole. 
It is also rounded upon its lower surfaces at each end, and 
provided with a spherical-headed screw (sunk below the sur- 
faces out of the way of work catching against it), all of which 



WMMk 



. 



L 


__ 71 — 


Mgg| 


^^%m%mmwmwy 


<* 

< ' 


HI 


■■ 




, . 



Fig. 149. 

allows it to accommodate itself to die-plates of somewhat 
varying thicknesses. 

In Fig. 149 is shown a bolster and ram into each of which 
the dies are screwed, being revolved by a straight wrench 
in holes h h' , or by making the dies polygonal in shape, or 
otherwise. Oftentimes with shanks of this kind the die U 
is made higher, as in Fig. 150, with a squared or hexagonal 
portion to the shank at S'. This construction is very com- 
mon with round dies of small size, such as are used for can- 
making, etc. 



8o 



PRESS-WORKING OF METALS. 



In Fig. 151 is shown a horizontal cross-section, at a point 
just below x, of a ram like those in Figs. 147 and 148, the 
common form of dovetail slide-bearings being embodied. 
This, however, is sometimes varied to some of the other 
forms shown in Figs. 15 to 20, Chap. II. Incidentally a 



) 1 




Fig. 150. 



Fig. 151. 



Fig. 152. 



Fig. 153. 



flange, /'/' (shown also in Fig. 154), is embodied in this ram, 
although it might be omitted as far as the other features de- 
scribed are concerned. In Fig. 152 is shown a similar section 
of a ram fitted with a separate clamp, as in Fig. 155, but with 




Fig. 154. 

tap-bolts to pinch it tightly upon the die-shank when inserted 
in the round hole, or punch-socket, shown. In Fig. 153 is 
shown a modification of the latter form where the hole or 
socket is of rectangular form, set diagonally, the clamp being 
in this case mounted upon studs and tightened by nuts run- 



DIES. 8 1 

ning thereon. This is perhaps, upon the whole, the best 
of all methods for holding shanks, especially when the socket 
is chambered out at the top, as at x, Fig. 155, so that if 
desired the shank can have a flange or projection entering 
into this chamber, and thus be held against any downward 
pull caused by stripping, etc. Such a socket will at the 
same time hold flangeless shanks just as well, and will accom- 
modate those of round, round slightly flattened, octagonal, 
or square sections. Furthermore, the size of these shanks 
need not be accurate, as the clamp can be screwed up to 
various points in its path so as to grasp sizes of somewhat 
varying diameters. 

Fig. 154 shows at L an extra large and heavy lower die. 
intended to be bolted directly to the press-bed without a 
bolster; also an upper die which is perfectly flat on the top 
and is secured to ram R by tap-bolts through flanges f'f 
(shown also in top view at Fig. 151) which are provided 
thereon. This is an excellent method for large cutting dies, 
which might slightly shift in a rotary direction, on a vertical 
axis, if fastened with a shank only. Sometimes, however, 
they are secured with both shank and tap-bolts. 

In Fig. 155 is shown a bolster, B, to which is fastened a 
chuck, C, by means of countersunk tap-bolts, although it 
might be fastened in various other ways, or might even be 
a part of the bolster itself, as in the next figure. In this 
chuck is secured a small cylindrical disk- or ring-shaped die, 
L, by means of a set-screw. This is a common form, espe- 
cially where there happens to be a large number of small 
dies which are of the same size outside, it evidently being 
much cheaper to mount them all in a common chuck in 
this way than to provide each one separately with a plate 
of its own. At C is shown an upper chuck, secured in the 
ram R by the method previously mentioned in discussing 
Fig. 153, although such a chuck may be mounted according 



PRESS-WORKING OF METALS. 



to any of the systems above described. It is shown that 
upper die U is secured by a pointed set-screw entering its 
shank, which latter, however, might be either tapering, as 







n 



ML 



B 



3 



L_ 



Fig. 155. 
in Fig. 147, or screwed, as in Fig. 149. The same reasons 
in favor of the chuck system apply here as have just been 
mentioned for the lower die. 





^~ 


// 1 


e 




"1 


W 




1 


w' 


B 


' / 


\r 


m 







Fig. 156. 
In Fig. 156 is shown another chucking system in common 
use, where the lower die L is dovetailed into the chuck B, 



DIES. 



83 



which in this case is shown as made in one piece with the 
bolster, although it evidently might be separate, as in Fig. 
155. The upper die U is shown as secured to the ram by 
the same dovetailed method, although when such dies are 
small they are sometimes dovetailed to an upper chuck, 
which is fastened to the ram by any of the methods shown. 
As here given, these dies are gripped by a wedge-shaped 
gib, IV, and also by set- screws bearing thereupon. These 
set-screws are, however, generally omitted, dependence being 
placed upon the wedge only. In some cases the wedge is 
omitted, the set-screws alone doing the work. In Fig. 157 
is shown, at B, another form of bolster-chuck, which is also 
represented in top view at Fig. 158. In this case the dies fit 




Fig. 157. Fig. 158. 

loosely inside of an upwardly projecting ring upon the chuck 
(or its substitute, four, or three, separate lugs) carrying the 
set-screws shown. Such a die may be varied in position by 
running each set-screw in or out to a more or less amount. 
It is one of the oldest methods for gripping dies, and is still 
used in many cases, but more especially upon drop-presses, 
where the die is solid and heavy and there is no other method 
provided for adjusting it laterally in place. It is, however, 
very objectionable for thin, ring-shaped dies for accurate cut- 
ting or forming work, as the die itself is generally sprung 



8 4 



PRESS-WORKING OF METALS. 



more or less out of its normal shape by the pressure of the 
screws. In this case the upper chuck is shown as a shank, S, 
provided with an enlarged screw-thread at its lower end, upon 
which a gland, g, is screwed. The gland forces the upper 
die U upward by means of its conical head, and at the same 
time holds it rigidly in lateral directions. This form is much 
used for round punching work not exceeding 2 or 3 inches in 
diameter, and is very convenient and cheap, as the ' ' punches ' ' 
themselves, which have to be frequently renewed, are of the 
simplest possible form. 

In Fig. 159 is shown a pair of shear-blades, the lower 
one, L, fastened to a chuck, C , or in some cases to a bolster 




c'w'i'i'k'i , u L 





Fig. 159. 

of similar shape, or in still other cases to the bed of the press 
itself, as made especially to receive it. At U is shown the 
upper blade, fastened directly to the ram, although in some 
cases an upper chuck is used. Two ordinary methods of 
fastening are shown, the upper one consisting of tap-bolts 
tapped into the blade, and the lower one of countersunk 
screws loose through the blade. In some cases such screws 
are made longer and mounted with nuts instead of screwing 
directly into the chuck. 

At Fig. 160 is shown one of the common methods of 
fastening double-action dies, for drawn-work, to the ram of 
a double-action press, R, which is usually provided with 



DIES. 



85 



projecting flanges through which tap-bolts run down into the 
flanged upper die U. As shown, this die is centered by a 
tenon projecting upward into the ram, the bolts being some- 
what loose in their holes. The inner upper die (sometimes 
called a drawing-punch) U' is shown as fitting and guided by 
the interior of the die U. Its shank at 5 is shown as fitting- 
loosely in plunger P of press, so that if there are any inac- 
curacies due to wear or other causes it may be rigidly kept 
in alignment by the die itself. A common method of holdino- 
U from dropping out of plunger embodies a small slidino- 
bolt or other device, not here shown, engaging in an annular 
groove running around .S" near its upper end. 

In Fig. 161 is shown a die not guided by a tenon, but 



r^ 




a H h 



Fig. 160. 



Fig. 161. 



Fig. 162. 



y 



resting with its flat surface against ram R, being secured by 
sliding hook-headed clamps. The inner die U' is screwed 
into the plunger, the same as in Fig. 149, and the outer die 
is supposed to find its own position before being clamped to 
place. In Fig. 162 is shown the same arrangement as regards 
the plunger, but with a threaded socket in the ram. into 
which the upper die is screwed. Sometimes a chuck, the 
upper part of which is fitted to the ram in the same manner 
as is the die itself in Figs. 160 or 161, is used, thus getting 
the advantage of one chuck which will answer for several 
small dies. The lower dies are not shown in the last three 



86 PRESS-WORKING OF METALS. 

figures mentioned, as they are fastened by some of the vari- 
ous methods shown for single-action dies. 

In general, it may be said that a mode of fastening dies 
which will fulfill the following conditions in any particular 
case will be found most satisfactory: I. Great rigidity and 
absolute security against displacement. 2. Quickness of 
manipulation, so that dies can be rapidly set and unset. 3. 
(For some kinds of dies) capability of revolving the dies about 
their vertical axis to various desired positions in the ram or 
upper chuck; and below, either directly upon the bolster 
or by revolving the bolster itself, or any lower chuck that 
may be used. 4. Interchangeability, as previously referred 
to. 5. Cheapness of design in one or both dies. There 
are in common use various methods besides the ones shown 
in the pictures. These, however, will give a general idea 
of the most usual methods. The fastenings for upper and 
lower dies, as shown in the various pictures, do not neces- 
sarily go together respectively, as, for instance, the lower 
die in Fig. 147 might accompany the upper die in Fig. 148 
or 149, etc. ; and almost any of them could be freely changed 
about at will. Hereafter in this treatise the simple form of 
upper and lower dies shown in Fig. 148, each consisting 
of a small cylinder surmounting a large one, will be used, 
wherever suitable, as a conventional diagram representing a 
pair of dies. 

Accuracy and Durability. 

In making or purchasing dies, after considering what gen- 
eral mechanical forms as above mentioned are best suited to 
his case, the die-user should pay especial attention to getting 
the proper — not necessarily high — degree of accuracy and 
durability to suit his particular work. In some cases the 
accuracy must be very great, as, for instance, where certain 
pieces of work produced by various dies must assemble to- 



DIES. 87 

gether and properly fit each other. In this case the dura- 
bility of certain working surfaces is very necessary in order 
that the sizes dependent thereon should be maintained as 
nearly uniform as possible. In other cases accuracy is not 
necessary, as, for instance, with various kinds of ornamental 
work, where mere appearance is the chief desideratum. Such 
dies may, perhaps, be required to have certain surfaces dur- 
able for the sake of maintaining the proper artistic effect 
or of avoiding wrinkles, etc. In other cases, however, there 
may not be any good reason for special durability, except 
avoidance of too frequent repairs or renewals. How frequent 
is a matter which depends wholly upon the required produc- 
tion. If, for example, only 1000 pieces of a certain soft- 
brass ornament are wanted in a year, as is the case in some 
gas-fixture manufactories, it would be foolish to make accurate 
hardened steel dies, because dies of the softest, cheapest 
material would run without any apparent wear for the hour 
or two required to make this quantity. 

If, on the other hand, these dies were required to run 
every day and all day, making many millions of pieces each 
year, then the greater the first cost, with its consequent dura- 
bility, the cheaper, as a rule, the dies would be in the long 
run. 

Some Specimen Dies. 

In Figs. 163, 164, and 165 are shown perspective views 
of various lower chucks. In Figs. 166, 167, 168, 169, 170, 
and 171 certain forms of fruit-can dies are pictured, this 
whole group, as well as the above-mentioned chucks, being 
assembled at random from cuts in the catalogues of various 
die-manufacturers. They are given here simply to show 
some of the designs in practical use — not necessarily as things 
of beauty and joys forever. 

In Fig. 172 is shown in one group a complete set of dies 



88 



PRESS-WORKING OF METALS. 



for manufacturing such parts as could be made with dies of 
a certain design of lantern, used by one of our large railway- 
companies. They are given merely as an illustration of the 
appearance such tools may assume in practice, and to give 
an idea to the uninitiated of the large quantity of dies re- 
quired to produce a comparatively simple-looking article. 
Such a group represents a great many hundreds of dollars 
for the actual cost of the dies included therein. Each pair 




Fig. 165. 
of dies, nevertheless, will cheaply produce millions upon 
millions of pieces, all practically alike, and each having a 
value perhaps of only a fraction of one cent. 



Composite Die Construction. 

Although many dies are made of one piece of metal, 
especially if of a simple shape, such as round and square 
cutting dies, etc., yet it is often desirable, in the interests of 
original economy of construction as well as durability, to 
make a die more complex in itself, by building it up with a 
number of parts. This not being a treatise upon die-making, 
the details of various constructions of the kind in question 
can hardly be here described. An instance, however, may 



DIES. 



8 9 



be mentioned, which carries this principle to rather an ex- 
treme point. With the tools used for cutting armature-disks 
for electric motors it is often necessary to cut say from 10 to 
300 deep narrow notches around the edge of a disk of sheet- 
iron, varying anywhere from six inches to four feet in diam- 
eter. These are sometimes cut separately in an " indexing " 
machine, but when it happens that dies are required for 
producing a complete disk at one stroke, including the pe- 




Fig. 166. 



Fig. 167. 




Fig. 168. 




Fig. 169. 



riphery itself, the central hole, certain key-seats and bolt- 
holes, as well as all the notches, it is obvious that the diffi- 
culty of making either a punch or a die in one piece would 
be very great, to say nothing of the impossibility of keeping 
everything exactly in shape, without warping, during the 
process of hardening, together with the strong probability 
of some of the teeth or other delicate parts being cracked 
at the same time. Even if finished successfully, the after 
breakage of a single tooth would, with such construction, 
ruin the whole die. It is therefore customary to insert all 
the hardened-steel teeth, and other cutting- edges, in iron or 



QO 



PRESS-WORKING OF METALS. 



soft-steel plates, fastening them in some way so that any one 
tooth may be removed, for repair or replacement, if desired. 
Other cases of built-up construction are seen in gang 





Fig. 171. 




punching tools of various kinds — also in the combination 
cutting-forming dies used to produce fruit-can tops and such 
like work. 



DIES. 9 1 

Changeable gang-dies are sometimes made with each indi- 
vidual punch or die, 01 both, removable so that others can 
be substituted. Following such a method embossing punches 
(as for stamping letters, etc.) are in some cases clamped to- 
gether in a "form," after the manner of printer's type. 

Heights of Ram and Dies. 

In adapting dies to a given press which is known to be 
of the right kind and size, after finding that the lower die 
will lie upon the bolster (or perhaps upon the bed, direct) 
properly fastened thereto; and that the upper die can be 
secured under or into the ram, with or without a special 
chuck or bushing; the next most important consideration 
is the matter of working ram height. The first condition to 
ascertain is the " shut height " of the dies (let us call it Ji) 
and also the " open height " (77), in cases where it is definite, 
which it usually is not. If not, the minimum height that 
will answer, to receive and deliver the work, may be taken 
{H'\ 

The measurements should be reckoned from the main 
top surface of the upper die — without counting knockups, 
shanks, or other projections that enter into the bed, bolster, 
or ram. Calling the bolster thickness B, the press-stroke 
5, and the working ram height, up from bed, when at top of 
stroke, R, we obviously have R=B -\- h -\- S and R = B -f 77 
or 77'. If then the specification of a press shows an " open 
height from bed to ram" equal to R, or, if greater, with 
the excess covered by the ram's adjustment, then it may be 
supposed to receive the dies. Some little of the excess 
just mentioned is desirable, to avoid the need of accurate 
heights in making and repairing dies. 

In cases where there is no bolster B of course becomes 
zero in the formula. With punching-dies h is obtained by 



9 2 PRESS-WORKING OF METALS. 

giving the proper " lap " of punch into die. With double- 
action dies the ram height and plunger height should be 
considered separately. 

Die Lubrication. 

Many dies are run without any lubrication whatever, but 
they will obviously last longer if treated in the same way as 
are other wearing surfaces. It is difficult to apply oil directly 
to the dies themselves, but it is sometimes customary to 
run a sheet of metal, which is being worked, under a felt 
roller, or a brush, or a pad of some soft material, which is 
kept saturated with oil or other lubricant. This is especially 
necessary in the case of drawing-dies, where the metal is 
forced between the punch and die through a considerable 
distance, with a rubbing action, often under considerable 
pressure. The material used for such lubricants is frequently 
sperm-oil, or almost any kind of grease having a good body. 
It is often objectionable, however, to have the finished work 
coated with grease, which is difficult to remove, to say noth- 
ing of the expense of the lubricant itself. It has been found 
that for working sheet-brass in certain ways soap-suds, which 
is both cheaper and cleaner than oil, answers a very good 
purpose. There are also various liquids in the market which 
are made purposely, and which probably consist of some modi- 
fication or mixture of grease, soap, water, etc. For drawing 
steel tubes a thin mixture of whitelead and grease, prefer- 
ably tallow, has proved an excellent lubricant. 

In some cases an occasional blank, or other piece of the 
metal being worked, is greased (say one out of every two or 
three dozen), the rest being fed dry into the dies. This 
of course keeps them somewhat lubricated. In many other 
cases no lubrication at all is practiced — especially with shallow 
work, and when the metal is of a so-called " greasy" nature, 
like tin-plate, for instance. Even with the latter, however, 



DIES. 93 

a lower percentage of breakage may be attained by occasion- 
ally rubbing the surfaces of the dies or the metal with a lump 
of paraffine, which of course deposits but a very thin film — 
not sufficient to soil the work. 

Nomenclature. 

As before stated, the various dies herein treated will be 
named functionally, but it must be remembered that the 
functions themselves are not commercially named with much 
regard to uniformity or good logic. Such inconsistencies as 
may appear will doubtless be condoned by the charitable 
reader, in consideration of the present " state of the art " 
of lexicography as applied to mechanics. 

Regarding the individual membership of a " pair of dies," 
it may be remarked that the word " punch " is very generally 
used to designate an upper die, whether cutting, forming, 
drawing, or otherwise, but this practice is not universal. In 
many cases " upper die " is the better term — for one reason, 
because the word punch is also used as a verb to denote the 
operation of punching and as a noun to designate the press 
itself, which is often called a " punch," especially if used 
for small holes in thick metals. As applied to one of two 
coining-dies, or to certain forms of upper combination-dies, 
etc., the word is entirely a misnomer. To avoid ambiguity, 
therefore, the term " upper die," when used herein, will des- 
ignate the die which is usually attached to the press ram — 
that is, in cases where the ram is not inverted. In the latter 
contingency, and in the case of horizontal presses, etc., some 
additional definitions might become necessary. Where there 
are three, rather than two, dies in a set, as with ordinary 
drawing-dies, it will be proper to term the inner upper one 
a punch, while the one surrounding it (sometimes called a 
blank-holder) will be known as the upper die. 

Another pair of terms frequently used are " male die" 



94 PRESS-WORKING OF METALS. 

and " female die" — meaning conventionally, of course, the 
one that enters and the one that is entered, respectively. 
These are convenient names as applied to punching, cutting, 
and some sorts of forming dies, etc., but, being thus restricted, 
they can hardly be used in a general sense. Applied to cer- 
tain kinds of embossing-dies they are respectively synony- 
mous, perhaps, with the terms " cameolike " and " intaglio- 
like." 



MATERIALS AND MEASUREMENTS, 95 



CHAPTER V. 

MATERIALS AND MEASUREMENTS. 

Commercial Metals. 

HAVING analyzed to some extent the tools used in the 
art of special metal-working of which we are treating, it 
will now be well to glance at the general nature of the ma- 
teiials worked by these tools. Although my title speaks of 
" metals " as the general name for these materials, the term 
may be qualified somewhat by occasionally including certain, 
forms of non-metallic substances in the forms of sheets and 
bars, which are often treated by the presses and dies ins 
question in an exactly similar manner to the metallic ones. 
These substances are mostly pasteboard, paper, cloth, leather,, 
thin slabs of wood, and a variety of other artificial fabrics 
resembling them in general characteristics — that is, so far as 
the most ordinary press operations are concerned. By proc- 
esses analogous to coining a great number of plastic materials 
may be worked in dies, but to some of these further reference 
will be made in a later chapter. 

It will hardly be necessary to give here a list of all the 
press-worked metals in common use, nor to deal with the 
origin and metallurgy thereof. The most common (perhaps 
about in the order named) are Iron, Steel, "Tin-plate,'" 
Brass, Aluminum, Copper, Zinc, " Britannia," Silver, Lead r 
Nickel, Gold, and Platinum. They are all ductile and work 
well when in proper condition. Not the least so is our new 
and beautiful aluminum, which seems to be destined to 
a marvelous future development, but which only a very 
few years ago would have appeared at the end of the above 
list. Its behavior under the action of dies is admirable.. 



9 6 



PRESS-WORKING OF METALS. 



The various alloys analogous to brass, such as the bronzes, 
" german silver, etc,, are too numerous to specify in detail. 
Any of the metals mentioned can usually be procured in the 
form of sheets, bars, or wire. 

In Figs. 173, 174, 175, and 176 are shown a few of the 
most ordinary various forms of bar-metal in common use, 
their cross-sections being circular, semicircular, and rectangu- 




Fig. 178. 

lar, respectively. In Fig. 177 is shown part of a sheet of tin- 
plate and in Fig. 178 a roll of sheet-brass. These latter, and 
in fact all sheet-metals, are obviously but very thin, wide bars, 
and there is, therefore, no vital distinction between them and 
any other flat bar, like Fig. 176, the difference being only in 
degree, and not in kind. As a practical matter we shall find 
that such bars as are here shown (and others) are frequently 
worked in the same machinery as are the sheets, which differ 



MATERIALS AND MEASUREMENTS. 97 

from them only by being thinner and wider in their general 
proportions. In addition to the above and other common 
forms of bars, triangular, hexagonal, octagonal, etc., have 
been developed in recent years a great many special cross-sec- 
tions for iron and steel bars which come under the general 
category of " construction iron " and " shapes," their most 
general use being for the frame-work of ships, buildings, and 
bridges. The above terms are obviously not very logical, 
as all the other forms mentioned are also used for construc- 
tion, and they all have some shape. 

The most used cross-sections for the metal in question are 
as follows: I, T, L, C, 1, their respective commercial names 
being I-beams, tees, angles, channels, and Z-bars. Their 
degree of commonness is probably about as in the order 
given. 

Besides the above types, there is the analogous and still 
more familiar tee-rail, with its various modifications, which 
is used in such enormous quantities upon all the railways 
of the world. There are also wrought-metal pipes of many 
sizes, usually of circular section, but not always. Then, 
too, there is wire of almost every size, shape, and material, 
which of course is really of the same nature as bar-metal. 

The above-mentioned metallic forms, which it is hardly 
necessary to here describe in further detail, are all, in com- 
mon, frequent victims of the rapacious jaws of some member 
of the press " menagerie " exhibited in the previous chapter. 

A buyer of any of the materials in question should of 
course familiarize himself with the exact commercial names 
pertaining to their different kinds, qualities, sizes, and 
methods of measurement at the time and place of his pro- 
posed purchases. This warning is uttered because of the 
considerable variations occurring in different locations and 
times in the nomenclature of both the articles themselves 
and the gauging-tools by which they are measured. 



98 PRESS-WORKING OF METALS. 

In this country and in Great Britain the English inch, and 
the fractions thereof in common use, are almost always used 
to designate the larger sizes of bar- and sheet- iron, steel, 
and copper, as well as brass. Thus, for instance, bar-iron is 
known as f-inch round, i-inch square, 4X2 inch, and so on. 
The wider bars, usually called plates, such as are used for 
boiler-making, ship-building, etc., are also usually designated 
by their dimensions in inches. When, however, round bars 
become so small as to be called wire, which is generally under 
\ inch in diameter, and of a length sufficient to coil, and 
when sheets become too thin to be described by ordinary 
inch fractions, then trouble commences. This trouble arises 
from the innate foolishness of the human heart, which cleaves 
to that which is old, no matter how absurd, and hesitates 
long about adopting the new, however permeated with com- 
mon sense. 

Wire-gauges. 

The last remark refers to the vexed question of the so- 
called wire-gauges, which might occupy the whole of this 
book if treated exhaustively. The only reason for devoting 
the next few pages to so apparently trivial a subject is the 
desirability of a metal-worker making himself fully acquainted 
with the pitfalls into which he is liable to tumble when buy- 
ing his materials by a numbered thickness. 

It was Carlyle, if I remember aright, who said that the 
population of England were so many millions — mostly fools. 
However indignantly we may repudiate the descriptive por- 
tion of the distinguished cynic's remarks as applied to the 
people of our mother country in general, we can scarce but 
admit the partial foolishness of that portion of the population 
who have been engaged at various times during a century 
past in the industry of inventing wire-gauges. In America, 
too, we find that either heredity or example, or both, has 



MATERIALS AND MEASUREMENTS. 99 

caused a further development of this pernicious industry, 
and that the crowning absurdity of all its products has been 
legalized in the United States by an act of Congress taking 
effect July I, 1893. 

One of the chief points about this remarkable latest 
" standard " is that it is almost everything it should not be, 
and fails to be almost anything that it should be, utterly 
ignoring many attributes that should be embodied in a good 
gauge, some of which are as follows: 

(a) The popularity and universality which are necessary 
to secure definiteness of measurement in the commercial 
world. (I?) Suggestiveness, preferably by making its unit of 
measurement in harmony with some other well-known unit, 
as, for instance, the English inch or convenient fractions 
thereof, (c) A logically progressive scale, with the smaller 
numbers for the smaller sizes, rather than a retrogressive one. 
{d) Uniformity of names or numbers, as, for instance, from 
unity upward, rather than mixing in a number of ciphers 
having no meaning in themselves, (e) A uniform or uniformly 
increasing increment in each successive size. {/) Capacity for 
additional sizes, either smaller or larger than the original 
ones, or interpolated between the same, as requirements at 
first unthought of may afterward occur. 

In the table on page 103 are given the dimensions, in 
thousandths of an inch, of 13 different American gauges, 
whose nominal size or number is shown in column A. On 
page 105 will be found a table giving in like manner the dimen- 
sions of 12 different foreign gauges, with the numbers in its 
column A. These numbers are not continued beyond 50, 
although in a few cases the gauges themselves extend to a 
distance which might too far trespass upon the reader's 
patience. In giving the inch values the decimals have not 
been carried out beyond three places of figures, although some 

of the gauge numbers run to millionths and even billionths of 
t. or C. 



IOO PRESS-WORKING OF METALS. 

an inch. In cases where these transcendental figures have 
been dropped a plus sign has been inserted, the third figure 
remaining normal, although the quantity would really have 
been better expressed in some cases (where followed by a 
figure larger than five) had such third figure been increased 
by one. For the practical purpose, however, of comparing 
the degrees of foolishness embodied the three figures in 
question will doubtless be sufficiently accurate. The values 
given in the tables have been carefully compiled from a 
variety of sources, including both English and American 
engineering handbooks, catalogues of gauge-, screw-, wire-, 
and sheet-makers, etc. 

Some similar work has been recorded in a chart gotten up 
by Dr. S. S. Wheeler, in which he has plotted a graphical 
comparison of all the principal gauges. This is a valuable 
addition to the literature of the subject. 

An inspection of column A will show the absurdity (for 
any new gauge at any rate) of using groups of ciphers in 
advance of unity. The first group given can easily be re- 
membered by thinking of Wordsworth's We-are-seven, Con- 
way-dwelling, cottage-girl, and has the advantage of requiring 
counting to identify it — thus preventing undue haste. In 
practical use it is probably pronounced number seven-naught. 
In column B we see again our new national standard, as 
referred to upon a previous page. In column C we have 
the real " American gauge," so called, which is largely used 
for measuring sheet-brass and sometimes for brass wire. The 
best thing that can be said of it is that it is the least bad of 
the whole lot, being scientifically designed so that its meas- 
urements will plot a parabolic curve with a uniform reduction 
of 1 1 per cent between each consecutive size. It is thus 
better proportioned to meet the generality of sizes required 
than are the other ones, but it has many of the faults com- 
mon to them, as, e.g., being retrogressive, starting with four 



MATERIALS AND MEASUREMENTS. 10 1 

naughts, being expressed in odd thousandths, and even mil- 
lionths, of the English inch, etc. The notch gauge in actual 
use for measuring these values is a beautiful tool — as might 
be expected of a product of the eminent engineering firm 
who designed it and whose name it bears. 

In columns D, E, F, and G we have other arbitrary stand- 
ards, the first three of which seem to bear a close relation 
to each other. Possibly they may have, long ago, been 
evolved from some common source by the interesting copy- 
ing process of measuring old worn-out gauge-notches to make 
new ones by. The music- wire gauge shows a decided change 
of tune, being the first with progressive numbers yet brought 
to our notice, though apparently being just as unsystematic 
as all the rest. 

In column H we have another progressive gauge whose 
figures, regarding Y^Qy- inch as a unit, are the respective square 
roots of iooo times the gauge number in column A. This 
probably may be convenient to electricians, some of whom 
compare all cross-sections of their wires by a special unit, 
the " mil," which is a denomination of a sort of special " cir- 
cular square measure," so to speak. The particular gauge 
numbers selected, however, do not appear to run up with a 
uniformly increasing increment, as is shown by the series 3, 
5, 8, 12, 15, etc. This gauge, as will be seen in the lower 
half of the column, advances by fives to 50 and goes beyond 
in the same way to 100; thence to 200 the advance is by 
tens, and after that by twenties up to 360. 

In column I we have another progressive gauge which 
appears to be a little more systematic than some of the others, 
as the sizes are expressed in whole thousandths, and run 
with a not wholly crazy series of increments, though why 
near the end of the table the measurements should jump 
suddenly from £ inch to 1 inch between two consecutive 
numbers, and this for measuring sheets as thin as zinc is 



102 PRESS-WORKING OF METALS. 

usually made, is not quite comprehensible. Neither is it 
apparent why it starts where it does, or for that matter, 
why it goes on, or stops, or is. 

In columns J and K we have two more arbitrary and re- 
trogressive gauges with no special features of interest. They 
both continue onward in the same style to No. 60. The 
drill-rod gauge is thereafter continued further, as a sort of 
supplement, in a progressive form, with letters for names 
instead of numbers, A representing .234 inch and Z .413 
inch. The increments between are neither uniform nor uni- 
formly increasing, but run in a sort of a "wild-cat" series 
somewhat thus: 4, 4, 4, 4, 7, 4, 5, 9, 5, 14, 7, U, 7, etc., 
with various other numbers interpolated. 

In column L we have a progressive gauge for measuring 
American screws which seems to be founded upon nothing 
and to start nowhere, except that its increments are approxi- 
mately .013 each. In column M we have a retrogressive 
gauge used by some of the large sheet-iron manufacturers, 
but, like most of the others, the question why it did not 
die before it was born will remain one of the conundrums 
of the ages. Its comparatively slight difference from the 
Birmingham gauge in common use must make it extremely 
inconvenient in practice. The next gauge, in column N, 
is a progressive one, and is, as far as I know, the only one 
used by glass manufacturers. Its numbers, like several of 
the others, are not consecutive, and certainly seem to skip 
around in a rather lively fashion. They appear to be with- 
out any particular definiteness, either in position or in rela- 
tive measurements. 

In column O in the next table, page 105, we have a re- 
trogressive gauge which is, I believe, the only legally stand- 
ardized one in England, it having been adopted by the Board 
of Trade some years ago. It seems to be founded upon the 
older gauges somewhat evened up, so to speak, but appears 



MATERIALS AND MEASUREMENTS. 



IO3 



A 


B 


c 


D 


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F 


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The above values all in inches. 



104 PRESS-WORKING OF METALS. 

to have no special relation to anything else on earth or in 
the heavens. 

Column P represents the well-known Birmingham, or B. 
W. G., or Stubs, gauge, which is almost always referred to 
(by some or any or all of these names), in this country, at 
least, when wire and iron and steel sheets are designated 
by number, although brass wire is sometimes, as before 
stated, measured by the Brown & Sharpe gauge. The gauge 
in question is often referred to in this country as " English 
standard," these words sometimes being stamped upon the 
gauges themselves, even in the factories of the best makers. 
This is evidently a misnomer, in view of the fact that Eng- 
land seems to have a dozen or so standards, one of them (not 
this one) being legalized, as before mentioned 

In columns 0, R, S, T, U, V, and W we have another 
pestilent brood of gauges starting and ending nowhere in par- 
ticular, all different, all retrogressive, and' all belonging appar- 
ently to the class of literature the reading of which might 
have made Carlyle so cynical. It will be noticed that no less 
than three of the gauges in this table enjoy the adjective 
" Birmingham," and the names of the others are rather un- 
certain, some being derived from places and some from people. 

In gauge nomenclature it may be observed that, besides 
having one name for several different things, the same thing 
has several names, as is shown by more than one of the in- 
stances given. The Lancashire gauge, shown in column S,. 
goes on beyond the figures tabulated to No. 80, which is 
.013 inch in size. It then has a supplementary progressive 
series named by letters from A to Z, the same as does the 
gauge already described in column K. After that, however, 
it indulges in a certain vagary by starting with No. Ai, whose 
value is .420 inch, and onward alphabetically to No. Hi, 
with a value of .494 inch. 

In column X may be seen the first glimmer of common 



MATERIALS AND MEASUREMENTS. 



105 



A 


O 


P 


Q 


R 


s 


T 


U 


V 


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X 


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004+ 








096 




.004+ 






.040 






4i 


004+ 








°95 
















42 


004 










091 
















43 


003+ 










086 
















44 


003+ 










084 
















45 


002+ 










080 










.045 






46 


002-f- 










078 
















47 


002 










076 
















48 


001+ 










°73 
















49 


001+ 










070 
















5° 


001 








067 










.050 







The above values all in inches. 



106 PRESS-WORKING OF METALS. 

sense yet appearing as recorded by history in the industry 
of gauge-inventing. Previously everything had been al- 
lowed to grow up of itself in the most haphazard manner, 
but here we see the work of the practical mind of Sir Joseph 
Whitworth, who, as soon as he tackled the subject, hit upon 
the obvious and only sensible way, in a country using the 
English inch, of designating the small sizes in question. 
This was, of course, to express them in inches, like other 
measurements used in mechanical work, which he did while 
retaining the old word " number " as a prefix — probably with 
a view of catering to the prejudices of a gauge-using people. 
This gauge in its complete form extends onward beyond the 
table to No. ioo, increasing by fives; thence to 120 by tens; 
thence to 180 by fifteens; thence to 300 by twenties; and 
thence to 500 by twenty-fives. The progression, it will be 
noticed, is not quite uniform in character, nor is the pro- 
gression in the lower part of column X, where the increment 
of two suddenly changes to five, beyond No. 40. This, 
however, may be forgiven, as a gauge of the kind in ques- 
tion is not limited to any particular numbers, it being perfectly 
logical to insert or omit, as may happen to be required for 
the particular work in hand. The system always remains the 
same, the sum expressed by the number agreeing with the 
quantity of thousandths of an inch involved. 

In' columns Y and Z we have two French gauges, both 
of which are progressive, but which have the usual non- 
relation to each other, or to any other principle, person, or 
thing. It is but fair to state, however, that when expressed 
in millimeters (which are not given in this table, in the in- 
terests of uniformity) they do not have so much of the " rag- 
ged-edge " effect as appears in the table. The progression, 
though, is not very uniform, and the actual sizes are in two 
places of decimals — that is, in hundredths of a millimeter 



MATERIALS AND MEASUREMENTS. \0J 

No. o being, in the Jauge de Limoges, .39 mm.; No. 5, .90 
mm., etc. 

In addition to the 25 gauges given in the tables there are 
a few odd ones, not so much used, which need not be given 
in detail. One of these is the French so-called millimeter 
gauge for iron rods, etc., which starts at No. P, equaling 5 
mm. ; followed by No. 1, 6 mm. ; No. 2, 7 mm. ; and thence 
onward, numerically, to No. 30, equaling 100 mm. The 
increments, however, are not uniform, being represented by 
1 mm. up to No. 16, and then increasing by steps of various 
sizes. Another gauge, also French, is used for zinc sheets, 
and is almost like the zinc gauge given in column I, varying, 
however, in some of its higher numbers. 

Still another gauge is the German millimeter, so called. 
This is founded upon the same correct idea as is the Whit- 
worth, No. 1 representing one mm., No. 2 two mm., No. 3 
three mm., etc. Practically, however, its sizes would ob- 
viously be too large and too far apart for ordinary thin sheet- 
metals or wire. Besides those above cited, there are a Ger- 
man, a French, and an English screw-gauge, and a German 
rivet-gauge, about which little is known here. Among the 
curiosities of gauge literature may be cited a hoop-iron gauge, 
the specification of which has been mislaid. It, as I re- 
member, playfully runs its numbers in reverse order part 
way through the scale, each having a small circle (like a 
degree-mark) printed after -it. It then duplicates these num- 
bers in natural order without the mark. Just what the sizes 
are I do not recollect, but practically hoop-iron is, I believe, 
nowadays sold by the B. W. G. Another curiosity in the 
gauging business is to have no gauge at all, as is the case in 
measuring tin-plate, whose thickness is commercially known 
by such names as Taggers when anywhere from .004 inch 
to .008 inch, as IC from .008 inch to .014 inch, as IX from 
.013 inch to .017 inch, as IXX from .015 inch to .019 inch. 



108 PRESS-WORKING OF METALS. 

etc. It will be noticed that these numbers lap each other 
in most cases, so that the same sheet might be called by 
either of two of the names given. There is, however, no 
attempt to measure this thickness, either by makers or users, 
it being guessed at by weighing a box of plates and knowing 
the number of sheets therein, these usually varying individ- 
ually to a considerable degree in any one box. The sorting, 
which is generally necessary, is done by shaking each sheet 
flatwise and judging of the thickness by the stiffness and 
weight. 

Another yet mor: foolish method of defining the thick- 
ness of sheet-metal, especially copper and lead, is to specify 
the weight in pounds or ounces per some unit of surface area, 
as so many ounces per square foot, etc. The solving of such 
puzzles as are involved in measuring operations of this kind 
requires either long experience or a mathematical mind of a 
high order. 

A supplementary set of sizes, lying between any of the 
gauge numbers of any of the 25 gauges mentioned, are in 
practical use, and are known by the following names: No. so- 
and-so easy, or bare, or scant, or loose, or light. Also No. 
so-and-so full, or tight, or heavy. Still another set of sizes 
are represented by these same adjectives with the word 
"rather" as a prefix; and still another set by the use of 
fractions, No. 15!-, etc., the \ serving as a suffix to, and in 
some way modifying, a regular gauge number. Furthermore, 
the people who use the above adjectives, with or without 
their qualifying adverb, and who use the fraction spoken of, 
do not generally make it very clear as to whether the scanti- 
ness, or fullness, or increase expressed by the fraction, refers 
to the actual size of the gauge-notch in question or to the 
numbers designated. Such indefiniteness in the case of re- 
trogressive gauges may of course reverse the meaning in- 
tended, and therefore the occupation of receiving and filling 



MATERIALS AND MEASUREMENTS. IOO, 

orders for sheet-metal, rods, nails, rivets, and wire becomes a 
somewhat puzzling one, to say the least. A customer merely 
states that it is to be No. so-and-so, qualified occasionally 
perhaps by the adjectives, etc., just mentioned, but says 
nothing about what gauge is meant, and how the adjectives 
and fractions are intended to be applied, nor whether he is 
depending upon duplicating material which has been meas- 
ured by some old gauge with worn-out notches. This is no 
fancy picture, but merely a portrayal of some of the misery 
daily occurring in commercial life. 

It is a noteworthy fact that with nearly all the gauges 
in common use the scale is retrogressive, having the smaller 
numbers for the larger sizes, which is manifestly an absurdity. 
The only excuse for this arrangement is that the numbers 
are given in the order of the operations of the wire-drawer, 
who originally adopted the ingenious and really somewhat 
scientific idea of calling his rolled-iron rod No. o ; his wire, after 
once being pulled through the drawing-plate, No. 1 ; after 
twice, No. 2 ; after thrice, No. 3, etc. This was all very well 
from his point of view, until he commenced to use larger 
rods, when he was obliged to lose sight of the beautiful num- 
bering of his operations, or rather to accept a false numbering, 
and to adopt a group of naughts for his starting-point. Fur- 
thermore, as different kinds of wire and different kinds and 
qualities of metal were afterward introduced, different grada- 
tions in drawing-plates were necessary, and thence probably 
arose some of the various other gauges which are shown in the 
tables on the preceding pages. This was a sort of natural 
evolution, based as usual upon ignorance of the future, and 
one which perhaps led the poor wire-drawer to think life 
hardly worth living, as the numerous gauges adopted from 
time to time gradually got mixed up, and when gauges of 
this sort were used for sheets and bars, as well as for round 
wire, etc. 



110 PRESS-WORKING OF METALS. 

In Fig. 179 is shown a side view, actual size, of the fa- 
miliar B. & S. gauge. It is made of sheet-steel about T V' 
thick, and is a very accurate tool — when new. This will 
serve also as a representation of the various other old gauges. 
They are usually thus circular, or else of an elongated octag- 
onal contour. 

A thorough discussion of some possibly successful and 
popular remedy for the evils indicated in this chapter, and 
a remedy, moreover, that should be international rather than 
merely American, might well require a volume to itself. In 




Fall Sise. 
Fig. 179. 

the limited space herein at command it is enough to say 
that the subject is constantly attracting more and more in- 
terest among engineers and other scientific men, with a prob- 
able result of some definite standard methods of dealing with 
the measurements in question being settled upon in the not 
too far-off future. Were it an Anglo-American question only 
there would be but little difficulty in popularizing the Whit- 
worth gauge, this being the only logical system where the 
English inch is the unit of measurement. Such gauges should 
be made not only for all varieties of sheet-metals, wire, rods, 
and bars, but for paper, cloth, leather, glass, etc., one sys- 



MATERIALS AND MEASUREMENTS. Ill 

tern answering perfectly for all. The apparent unnecessary 
magnitude of a gauge comprising every yoVo inch, say, from 
i to iooo, can be easily overcome by preparing notched 
gauges for particular trades and industries, containing only 
such sizes as are in common use therein. Each industry or 
group of industries needing about the same range could thus 
have as small and simple a gauge as possible, with all super- 
fluous numbers omitted ; and any gauge would absolutely 
agree with any other, whenever they happened to have any 
numbers in common. 

The real difficulty in this matter, however, looms up when 
we attempt to contrive an international gauge, which will be 
equally welcome to the peoples of the earth using the English 
inch and the French meter. It has been suggested that a 
gauge founded upon a hundredth of a millimeter as a unit, 
each number to express the quantity of these units embodied, 
would answer perfectly well for the whole world's use, and 
this view is advocated by a number of scientists in this coun- 
try as well as abroad. Such a scheme has the disadvantage 
for England, America, and Australia of not being easily trans- 
lated into and compared with our standard measurements. 
It has, however, the advantage of having a unit of about 
^-§Vo" i ncn > which for very small sizes is better than the xuW 
inch unit of the Whitworth gauge. Whichever of these two 
most feasible schemes may be adopted, the commercial and 
engineering world will certainly be happier and better there- 
for. One strong point in favor of the general principle herein 
advocated is that any of the notched gauges (which form 
seems to be popularly demanded) founded thereupon can be 
easily calibrated and kept in order by the ordinary microm- 
eters such as are now in use in all machine-shops, measur- 
ing by thousandths up to I inch, or similar ones arranged for 
the metric system. 

This very important subject is now being looked into by 



112 PRESS-WORKING OF METALS. 

a committee of the American Society of Mechanical Engi- 
neers, which will probably co-operate with committees from 
the other great national engineering societies. Interesting 
discussions have for some years past taken place in the va- 
rious society conventions, in one of which the adoption of a 
T"oVo" mcn un it f° r a numbered gauge was proposed and stren- 
uously advocated by the present writer, he at that time 
(May, 1889) not knowing just how far Whitworth had pre- 
viously gone in the same direction. Nobody appears to have 
ever seriously opposed this scheme, but there seems yet to 
be the inertia of a heavy mass of conservatism and indiffer- 
ence to overcome. Active forces have, however, been set in 
motion and it is earnestly to be hoped that before the twen- 
tieth century shall have dawned the civilized world will have 
forgotten its past incomprehensible foolishness in regard to 
the measuring of its smaller dimensions, and that some 
gauging system as simple and definite as it is universal will 
have been adopted as merely the embodiment of common 
sense applied to common things. 

A Proposed New Gauge. 

In following up and amplifying the Whitworth idea of 
notching it is very desirable that the gauge should be of 
some distinctive shape, which will not be confounded with 
any of the old gauges, thus preventing many mistakes. For- 
tunately none of the notched gauges in the market have been 
made of an elliptical contour, as shown in Fig. 180, which 
might be uniformly adopted as the only shape for such new 
gauges as are based upon the system in question. Among 
other advantages are general beauty of form and convenience 
for the pocket. This scheme was recently proposed by me 
before a joint committee of the American Railway Master 
Mechanics' Association and the American Society of Mechan- 



MATERIALS AND MEASUREMENTS. 



113 



ical Engineers, with an offer to freely assign any rights to a 
design patent which I might be entitled to. It was unani- 
mously, though unofficially, approved by all the members 
thereof, who decided that a desirable method of marking the 
notches in such a gauge was as shown in the picture, viz., 
by the three figures expressing the decimal of thousandths of 




Fig. 180 



an inch, with a very definitely marked decimal-point to the left 
of the same, and with the usual " inch-mark " (") above and 
to the right. This uniform use of three figures will tend to 
prevent mistakes in speaking of the sizes in question, which 
would not be the case if final ciphers were omitted and 
certain measurements were allowed to be expressed in tenths 
or hundredths by the use of one or two figures respectively. 



114 PRESS-WORKING OF METALS. 

In such case were a measurement, for instance, twenty-one 
hundredths, it would very likely be spoken of as " twenty- 
one thick " or " twenty-one gauge," in which contingency it 
could, of course, not be known whether twenty-one hun- 
dredths or twenty-one thousandths was intended. By the 
uniform system mentioned, however, such a measurement 
would, of course, be known as "two hundred and ten ,r 
rather than " twenty-one." 

A difficulty has been suggested as apt to arise in cases 
where measurements must be finer than in any given number 
of thousandth inches, this being that sometimes four figures 
would have to be used. Such cases will rarely happen in 
commercial life, but when they do the system will not be 
at all thrown out of gear by the use of an additional figure, 
provided that the decimal expresses it as ten-thousandths. 
This is lor the reason that such gauges are limited to sizes 
under I inch in thickness, and that therefore there are never 
more than three figures in practical use when working upon 
the thousandth basis. The use of four figures at once indi- 
cates, therefore, that the ten-thousandth basis has been 
adopted for the particular case in question. 

In regard to a name for this proposed gauge there is 
perhaps no definite consensus of opinion yet formulated. 
It was proposed as one scheme that such a tool be stamped 
with a large letter " M," as shown in the picture. This, 
being the Roman symbol for iooo, would give the general 
idea that such a number was used as a base of operations. 
This scheme might not be as logical as would one involving 
a definite name, but it has the merit of being new, so that 
there will be no danger of mixing the " M " in question with 
" B. & S." or " B. W. G." cr any of the other names; 
and it also has the very important feature of being short and 
simple, and therefore easy to speak and write. This brevity 
(as is shown in the popular naming of the elevated railways 



MATERIALS AND MEASUREMENTS. I I 5 

in New York by the single letter " L " and by numerous 
other instances of the kind) is, in our rapid modern life, an 
extremely important factor of popularity. There would seem 
to be but little difficulty in introducing a gauge of this kind 
where its shape, either to the eye or to the touch, would be 
absolutely distinctive, either in light or darkness, as would 
also the large M deeply stamped upon it. In ordering 
goods it would be necessary merely to say, " Send " so many 
"pieces of brass, M gauge .087." It would not be im- 
portant to write the inch-marks, and in verbal orders neither 
they nor the point nor the cipher would appear. Instead of 
the big M possibly a big D, the initial of the word " deci- 
mal," would be better, this adjective seeming so far to be 
the most popular. 

Referring more in detail to the picture, there is shown 
therein, drawn to real size, a gauge embodying somewhat 
the above ideas, and one, moreover, which could be notched 
and graduated to any desired set of sizes without upsetting 
the system involved. It would (wherever it happened to 
have any sizes in common with it) agree absolutely with the 
Whitworth gauge — and with common sense. The particular 
graduations shown in this case are not ideal, the sizes not 
running in a proper series. It is made as it is merely to 
show how the ordinary B. W. G. gauge would look with the 
proposed new system applied to it, the notches being a copy 
of the same from " No. 1 " to " No. 36," in actual size. 

In general, it may be said that the committees above 
referred to, as well as various other would-be reformers who 
have taken an interest in this question, have not publicly 
committed themselves to the advocacy of a national legal 
gauge of this sort. They think that such a tool is needed 
in the present emergency, and that its use is only in the 
line of carrying out the system of measuring that they are 
already doing with the ordinary micrometer gauge. These 



I 1 6 PRESS- WORKING OF ME TA L S. 

gentlemen are, presumably, perfectly willing to consider in 
future an international gauge for the use of the whole civil- 
ized world, which may or may not be founded upon the 
English inch or the French millimeter, or something else 
not yet worked out. 

Some of the desirable qualities to be sought for in select- 
ing a good series of numbers for a commercial gauge of the 
kind in question are as follows: 

I. The increments in the series should be uniform or 
should increase with a considerable degree of regularity, not 
decreasing at some points and abnormally increasing at others, 
etc. In other words, the numbers used as ordinates should 
plot as smooth and graceful a curve as possible, without re- 
entrant angles, and preferably approximating a parabola. 

2o The measurements in question should, as far as pos- 
sible, agree with the fractions of an inch in common use in 
our draughting-rooms and machine-shops, especially those 
founded upon the binary divisions thereof, as sixty-fourths, 
thirty-seconds, sixteenths, eighths, etc. 

3. They should also agree, as far as is consistent with 
other conditions, with the old gauges in common use, for 
the reason that metals measured by such old gauges are 
already now in the market in large quantities, and are more 
likely to be produced in future than are those measured by 
any new set of sizes. This is on account of the prejudice 
and force of habit of the makers thereof, and on account 
also of the special tools they have in use, such as dies for 
wire-drawing, etc. 

4. The numbers used should be as easily remembered as 
possible, and therefore the preference should be given to 
" round numbers," so called — that is, those ending in ciphers 
and fives. 

Keeping in view the principles above enumerated, and 
referring to the chart, Fig. 181, there will be seen in the 



MATERIALS AND MEASUREMENTS. 



117 



first column a series of 38 numbers (about enough to com- 
fortably fill an ordinary pocket-gauge), which, measured from 




Fig. 181. 
the vertical dotted line respectively as abscissae, will produce 
the curve shown. This is reasonably smooth and approxi- 
mates a parabola. 



Il8 PRESS-WORKING OF METALS. 

Furthermore, certain of these numbers are respectively 
equivalents, within a fraction of less than 70V0 inch in each 
case, of the popular draughting-room and machine-shop meas- 
urements T ^g, -gV- 3V, T V, ih t 3 6> and i inch, and a l so inci- 
dentally of j^jy, ys'o* ^00"' ToT> To> <nr> ~io> 21J' tV i ncn an d I 
millimeter. 

It will be noticed also that the Birmingham wire-gauge 
is represented by 15 equivalents, many of them exact. Bet- 
ter than this, the Brown & Sharpe gauge is represented by 
no less than 25 approximate equivalents, 22 of them being 
in a continuous series. These all agree within a fraction of 
less than yqVtt inch, and all but one of them within less than 
■ 2 ^ , it being impossible in most cases to make them en- 
tirely exact, as the Brown & Sharpe gauge is scientifically 
founded upon a parabolic curve and is expressed in full by 
decimals of the inch running as far as millionths. Such 
agreement with this gauge, which is undoubtedly the best 
of the arbitrary retrogressive gauges in use, is an important 
feature, as large quantities of sheet-brass and brass wire are 
commercially measured with it, and it is well known as the 
" American gauge." A departure from its measurements is 
made only at 0.050 inch and above, it being very desirable 
to embody the \ inch with the natural divisions thereof, and 
furthermore, it is usually unnecessary for a notched gauge 
to embrace any larger sizes than this, as the measurements of 
our plates and rods are, perhaps, most frequently expressed 
in thirty-seconds, sixteenths, etc., when above \ inch. Besides 
the old gauge numbers given in the chart, there are other 
omitted ones which approximate the proposed new sizes 
within a limit of from T oVo to ToVo- In most cases the differ- 
ence is not so great but what the new numbers would prac- 
tically cover all ordinary commercial requirements, never 
departing over 5 per cent from either gauge — the B. & S. 
or the B. W. G. — from some one of the notches. This is 
nearer than the average measuring is usually done. 



MATERIALS AND MEASUREMENTS. H9 

In regard to the fourth desirable qualification above men- 
tioned, the series of numbers given is not, of course, an ideal 
one, although pains has been taken to embody such easily 
remembered numbers as .005, .010, .020, .025, .040, .050, 
.080, .090, .100, .125, .170, and .25O0 The odd numbers 
between seemed necessary — in some cases to agree with de- 
sirable vulgar fractions, and in others to complete the series 
with a proper rate of progression so as to strike upon an 
average the greatest number of probable marketable thick- 
nesses of metal. 

In general, if anybody planning a set of numbers (to suit 
perhaps some particular industry) will arrange them as on 
the chart, measuring off their values to some desirable scale, 
and if, furthermore, he will see that the resulting curve plotted 
therefrom is an ordinarily decent one, pleasant to the eye 
and satisfying to the conscience, he may feel sure that he 
has gotten a useful gauge, and that no harm will be done 
by certain notches which may appear superfluous. These 
may seem interpolations for his present purpose, but in add- 
ing other sizes to his products in future these neglected 
notches will, by the law of probabilities, be likely to prove 
the " missing links " he was unconsciously looking for. 

Micrometers. 

In Fig. 182 is shown, real size, an adjustable gauge, 
commonly known as a " micrometer." It has a capacity 
for measuring thicknesses up to 1 inch — of course near the 
edge of the sheet only. Similar ones are made for \" , 2" ', 
and 3" work. They are graduated to read direct up to 
.025", and further by adding revolutions of the screw, each 
of which counts another .025". They are usually very accu- 
rately made, and some of them have a vernierlike graduation 
which reads to ten thousandths. 



120 



PRESS-WORKING OF METALS. 



In Fig. 183 is shown in real size, side and top views, a 
micrometer design contrived by the writer for a gauge to be 
carried in the vest pocket, and to be instantly read without 
the calculation required in those now in use. Obviously it 
has not their capacity, being intended for thin metals only, 
as, e.g., tin-plate, light sheet-iron, etc. It has, however, 




Fig. 182. 

the advantage of measuring some 2" from the edge of the 
sheet. It is not patented, and it is to be hoped that some 
gauge-maker will recognize its good points, if it has any, 
and put it upon the market. 



Annealing. 

It is taken for granted that the materials employed for 
press-working, especially in processes of distortion, which 
are more difficult than mere cutting, must be to some con- 



MATERIALS AND MEASUREMENTS. 



121 



siderable degree in a malleable or ductile physical condition. 
In the case of many metals when worked hot this freely flowing 
condition exists as a matter of course. When worked cold, 
however, it is frequently necessary to have them annealed 
before beginning operations. 

For cutting or punching, most commercial metals are in 
S P 




Fig. 183. 
a suitable state as found in the open market, except perhaps 
tool-steel, which is generally sold unannealed. 

For forming, drawing, coining, and analogous processes, 
especially where there is to be considerable distortion, and 
with such metals as steel, brass, nickel, aluminum, etc., 
which rapidly harden by the action upon them of hammers, 
dies, rolls, and other tools, care should be taken that they 
are in their " soft " rather than " hard " condition when pur- 
chased. This softness and ductility, however, is apt to dis- 
appear during certain operations performed in dies, and should 
be restored by re-annealing when the metal becomes so brittle 
as to be cracked or torn. In the case of drawing cups, shells, 
tubes, and such like this necessity for annealing often happens 
after the first one, two, or three operations. 



122 PRESS-WORKING OF METALS. 

Where many pieces of work are to be made, which thus 
require annealing, it is best to have special apparatus for the 
purpose, with a view of heating the metal without oxidizing 
it to such an extent as to form a scale upon its surface. Such 
scale not only wastes it away, but acts in many cases as a 
grinding material to wear off the surfaces of the dies, to say 
nothing of its effect in marring the surface of the work. 

One of the newer annealing processes (which I believe is 
patented) enables highly polished metal to be brought from 
the furnace with no scale of oxide whatever, the original 
brilliancy, if polished, being maintained throughout. This 
result is ingeniously attained by keeping the metal while 
being heated in a bath of gas containing no oxygen, the 
practical arrangement being the forcing of ordinary heating 
or illuminating gas into the air-tight receptacle in which the 
heating is done. Usually the fuel is this same gas, a small 
portion of which is shunted off, as it were, for bathing pur- 
poses, as above mentioned. 



CUTTING PROCESSES. 12$ 



CHAPTER VI. 
CUTTING PROCESSES. 

Explanatory.. 

Having more or less accurately formulated the ideas of 
writer and reader regarding tools and materials, we will now 
deal with actual processes, showing in such diagrams as may 
be necessary only conventional forms for shear-blades, dies, 
etc., and omitting as far as possible, for the sake of sim- 
plicity, pictures of the presses themselves or of the methods 
of fastening dies thereto. The details treated of will gen- 
erally require only certain views of the working surfaces of 
the respective dies and of the materials worked therein. The 
letters U and L will represent upper and lower dies respec- 
tively in their conventional sense, although it must be re- 
membered that the respective positions of these are, in prac- 
tice, sometimes reversed, or in some cases turned at right 
angles or at some other angle to their usual vertical position 
— as in horizontal shearing-machines, inclined presses, etc. 
The metal or other material when shown between the dies 
will usually be represented by dotted lines and will be marked 
M. It will be referred to as " the material," " the metal," 
or, oftener, perhaps, " the work," as may in each case seem 
appropriate. These remarks will apply also to subsequent 
chapters dealing with other processes. 

Chiseling. 

If we analyze cutting processes as performed in presses, 
we find a most primitive idea to be that of the chisel, or 



124 



PRESS-WORKING OF METALS. 



knife, as shown in Fig. 184. This is in a certain sense a 
form of coining or forcing the tool bodily into the metal. 
Practically it is an application of the wedge, which was prob- 





K 



L 
Fig. 186. 



Fig. 184. 



Fig. 185. 




U 



Fig. 187. 



Fig. 188. Fig. 189 



1 ^Lj 



Fig. 190. 




Fig. 192. 



— g 



Fig. 191. 




Fig. 193. 



ably carried out in antediluvian times, when the primeval 
metal-worker found a particularly sharp-edged stone and 
pressed it hard down upon his piece of copper or lead, that 
he might separate it and make the one twain. In modern 



CUTTING PROCESSES. 1 25 

practice this principle is carried out in the blacksmith's chisel, 
in the tinman's punch, in various sharp-edged dies for cut- 
ting shoe-soles or other articles of leather, paper, etc., and 
in that form of foot or power press known as a " sprue-cut- 
ter," which is usually made with two chisels meeting each 
other, as in Fig. 185, or more often with one-sided chisels, 
as in Fig. 186, these leaving less of a lump upon the casting, 
C, when the sprue, S, is removed. 

In all chiseling processes there is, of course, a tendency 
to raise a bur upon each side of the knife, as shown, exag- 
gerated, at the sides of £7 and L. Usually, however, this is 
partly crushed down by the sliding of the knife against it. 

Shearing. 

The next and most usual process for cutting materials 
embodies the principle of shearing, shown in its most prim- 
itive form in Fig. 187, where a certain part of the material is 
pushed away from a plane represented by one of its surfaces, 
as aa, Fig. 187, into another plane parallel thereto, by being 
slid past the other part of the material, which remains in its 
normal position. This sliding of certain of the particles or 
molecules past certain other ones constitutes the stress known 
in engineering by the general term of "shear," and is 
governed by well-known laws as to the resistance of the 
material itself. These laws it is not necessary now to define 
or formulate further than the reference which will be found 
near the end of this chapter to the pressures required for 
such shearing. 

In Fig. 188 is shown, in end view, a more usual form of 
shear-blades, the cutting-edges being made at an angle of 
about 75 between their two limiting surfaces, instead of 90 , 
as in Fig. 187. In Fig. 189 is shown the same blades as 
they often appear after practical use, with their edges rounded 
■off and their adjustment altered so that their vertical faces 



126 PRESS-WORKING OF METALS. 

do not touch one another. In Fig. 190 is shown the ap- 
pearance of a bar of metal as sheared apart at s with the dull 
blades just mentioned. In the left-hand piece the lower 
corner is rounded, while the upper corner runs into a sharp 
bur that has crept up between the blades. Just to the left 
is an indentation, n. caused by the compressive action of the 
blade itself. The other piece of metal is, of course, the same, 
but reversed in position. 

In Fig. 191 is shown, in vertical cross-section, a piece of 
sheared sheet-metal with the same rounded corner and the 
same bur at the top, but with a cleaner cut, as made by 
sharper and well-set blades. The bur and round corner are 
exaggerated, but they are usually present in some degree in 
all kinds of shearing and punching work. They must be 
allowed for even in working thin metals with sharp dies, as it 
is often a matter of consequence on which side of the work 
this slight bur shall appear, and which side shall have a 
slightly rounded corner. 

In Fig. 192 is shown a part of the frame of a press with, 
a pair of plain shear-blades mounted directly upon the bed 
and the ram respectively. In Fig. 193 is a similar view, 
with shear-blades made for cutting off round iron, there 
being a series of semicircular notches in each blade adapted 
to the sizes of iron to be worked. Upon this view there is. 
also shown an adjustable gauge, G, such as is often used for 
pushing a bar against, to regulate the length of the piece 
cut off. The two views shown are copied from various, 
machines commercially in the market, and fairly represent 
good average design. The same may be said of the mounted 
punch and die shown in Fig. 196. 

Dip or Shear. 

In Fig. 194 is shown a face view of the blades in Fig. 
187, the same being made parallel, so that all points along; 



CUTTING PROCESSES. 



127 



their cutting-edges will come into contact with the metal 
at the same time. This form is best (properly " beveled," 
as in Fig. 188) where the metal must not be twisted or other- 
wise disturbed, and is good enough in any case where it is 
quite narrow in comparison with its thickness, as with square 
bars. With such proportions it obviously is not practicable 
to much lessen the pressure required to do the cutting by 
dividing it up and extending it over a longer time. Such 

U 



Fig. 194. 



Fig. 195. 




Fig. 196. 

an extension of time and lessening of the pressure at any 
particular moment may sometimes be obtained, however, by 
making one of the blades, like the upper blade in Fig. 
195, with an inclination of the edge, commonly known as 
"dip" or "shear." This evidently is useful only where 
the width of metal cut is considerable. It is obvious that 
in such case one edge of the piece of bar- or sheet-metal is 
pushed down by the upper blade and depressed in advance 
of the other edge, thus producing a bending action across 



128 PRESS-WORKING OF METALS. 

the sheet which distorts it more or less from its original flat 
condition, as at M. This action is seen in the curling up and 
twisting of a narrow strip cut from a piece of paper with a 
pair of scissors, or a sheet of tin-plate with a pair of snip- 
shears. In many cases it does no harm, and we therefore 
see the great majority of shearing-machinery made in this 
way. This inclination of one blade to the other is usually 
somewhere between 5 and 15 . If the angle is too great, 
the tendency of the work is, obviously, to slide lengthwise 
of the blades, or toward the left, in Fig. 195. The greater 
the angle the easier the work is done by the machine and 
the more the sheet is distorted, and vice versa. 

It is very desirable that the word " shear," as designating 
the angle of inclination referred to, and also the act of me- 
chanically producing such inclination, should be changed for 
a less confusing term, as this word is already used in many 
cases for the press itself which does the shearing, and for 
each of the blades which are mounted thereupon, and for the 
act of doing the cutting-work itself. Thus in this connection 
we may easily have such an awkward and misleading sen- 
tence as the following: 

" Tom, shear half an inch the upper shear in the two-ton 
shear, that it may shear more easily by having more shear — 
and, I say, Tom, leave a sheer opening of an inch and a half. 

The quoted sentence reads like sheer nonsense. It is, of 
course, given as an extreme case of the evil referred to, but 
I have heard orders uttered which were nearly as confusing. 
The word in question is above used the first time as a verb, 
denoting the act of grinding more inclination upon one of 
the blades; the second time as a noui:, meaning the blade 
itself; the third time as a noun, meaning the machine in 
which the blades are mounted; the fourth time as a verb, 
denoting the act by the machine of shearing the material 
worked upon; the fifth time as a noun, designating a detail 



CUTTING PROCESSES. I2 9 

of construction of the blades, and the sixth time (differently 
spelled) as an adjective, denning the space bevveen said 
blades. In my own practice I am endeavoring to use the 
term " dip " as a substitute for " shear " in this connection, 
but perhaps may not succeed in inducing the public to accept 
it. This word is given by Webster as a synonym for ' ' slope 
and "pitch," and has in its favor brevity and crispness, to- 
gether with no danger of confusion with other terms apt to 
be used in the same connection. It also is correct from an 
engineering point of view (at any rate in the case of ordinary 
upright shearing-presses) as representing some angle of in- 
clination with the horizon, and it is already applied to such 
angles in mining parlance when speaking of mineral veins. 
It would also seem somewhat appropriate in speaking about 
gangs of punches as shown in Fig. 200, which are set with 
their lower ends in a series of different heights, that they 
may not enter the work .all at once but may bring the press- 
ure required for each cumulatively upon the press. In this 
case certain of the punches have a dip, so to speak, below 
the other ones, in the sense of reaching downward. A word 
often used in connection with such punches is " lead," mean- 
ing that one has the lead of some other one in first striking 
the work. To tools of this kind the word " shear " is hardly 
applicable at all, but the word " dip," if it could be generally 
introduced, would answer for all cases of punches as well as 
shear-blades. 

Punching. 

In speaking of the important operation of punching as a 
companion with shearing, both of them coming under the 
head of shearing processes when the term is used in its broader 
sense, and shearing, in its turn, being but one subdivision 
of the general class known as cutting processes, we again find 
ourselves in a state of disgust with word-inventors. This is 



130 PRESS-WORKING OF METALS. 

because the word " cutting" is used by practical men in a 
specific sense also, when defining certain dies, as an adjective 
almost synonymous with " punching." It is difficult to 
draw the line between dies known by these two names, but 
the former is usually applied to large sizes of " cut " in thin 
sheets of metal and the latter to small sizes in thick bars or 
sheets. Roughly drawing a line of demarcation, it might 
do to call the operation cutting when the thickness of 
metal is less than T \ of the longest diameter of blank, and 
punching when more than T V of the same. The former 
term would cover most of the press-work on thin sheet- 
metals and the latter on boilers, bridges, ships, etc. In 
this treatise no definite distinction will be made except as an 
approximation to the proportions above mentioned. 

In Fig. 196 appears a partial view of a deep-throated 
press frame, with a small round punch and die mounted in 
chucks set therein, and supplied with an adjustable stripped 
5. 

In Fig. 197 is shown, in vertical axial section (which, 
by the way, is the kind of view given in most of the pre- 
vious pictures where circular work has been represented, and 
which will be usually understood hereafter unless otherwise 
specified), a pair of ordinary round cutting dies, without 
dip, both working surfaces lying in planes parallel to each 
other. It is evident that such a pair of dies are in principle 
simply a pair of shear-blades, like Fig. 188, bent around 
into a circle, and that the same principles involved in ordinary 
shearing hold good. This statement may be somewhat 
modified where the diameter of the blank (this term " blank " 
meaning in general a flat piece of any shape cut from a 
sheet) is quite small in comparison with its thickness, as for 
instance in punching boiler-plate, etc. In such cases a little 
more force must be required to do the shearing, on account 
of the blank being tightly confined in the hole from which 



CUTTING PROCESSES. 



131 



it is pushed; while in doing the same amount of shearing in 
a. straight line the piece cut off usually falls freely away 
without friction. A thick blank of small diameter is some- 
times called a "punching" — also a "wad." The metal 
around it is in some cases termed the " margin." 

Fig. 198 purports to show an upper die or punch, such as 
is often used for boiler- work, etc., with its lower end made 
in a spiral form instead of lying in a plane normal to its 





Fig. 1 



u 

1 








\w s 




c 

lI 


i ) 


£m^ 


to* 




II 


h, ,111 1 


111 


1 




In Mil 




■ 


1 



Fig. 199. 



Fig. 200. 



axis. Various experiments with such punches have shown 
them to require somewhat less force to drive them through 
than in the case of the ordinary fiat-bottomed ones. In Fig. 
199 the same principle of dip is shown in the upper die U 
with its two " high- points " d d' . These strike the metal 
first, the bottom of. this die being scooped out as if it had 
been held against a cylindrical grindstone. For large diam- 
eters this is much better than a single high-point, as in Fig. 



132 PRESS-WORKING OF METALS. 

198, because the pressure upon the press ram is balanced, 
whereas with one point striking the metal first there is a 
tipping action which tends to spring the ram and upper 
part of the press frame out of a vertical position, and con- 
sequently to slide the upper die sidewise over the lower one. 
Such action often occurs in practice, to the considerable detri- 
ment of the cutting-edges, and great care should always be 
taken, where a die is over 2 or 3 inches in diameter at any 
rate, to see that it strikes the metal at two or more points 
equallv balanced about the vertical axis of the ram. Of 
course this cannot always be done, and in such cases a more 
rigid press will be required than in the other case. The 
lower die L in Fig. 199 is also shown " dipped," having in 
this case four high-points. In practice, however, one die is 
usually made flat, all of the dip being put upon the other. 
Which die should be flat depends upon the nature of the 
work. With a thin material, such as tin-plate, and with 
diameters, say, above 2 inches, this point is of little conse- 
quence, as both the blank and the sheet outside of it, if 
sprung out of flat while the die is going through, will readily 
be restored to a flat condition by their own elasticity. If, 
however, the metal is thick and rather non-elastic and the 
diameter small, it is evident that an upper die scooped out, 
as in Fig. 199, would bend the blank, perhaps beyond its 
elastic limit. In such cases, therefore, the upper die should 
be perfectly flat, that is, if no damage will be done to the 
sheet outside by its being bent as it rests on the dipped lower 
die. Usually in these cases this sheet outside is only " scrap " 
(the conventional term for all the waste metal), and such 
bending will make no difference. If, however, it too must 
remain flat, the only recourse is to make both dies without 
dip and use more pressure to drive them. In cases where 
mere perforating is done, that is, where the sheet outside the 
blank is the article required for use and the blank is regarded 



CUTTING PROCESSES. 1 33 

as scrap, the upper die should always be the dipped one — 
unless indeed their size is so large in proportion to the thick- 
ness of metal as not to signify. 

In general, it is better theoretically to have only two high- 
points upon cutting dies, either round or otherwise, as the 
metal which is sprung out of flat by reason of the dip is, in 
such case, simply bent into an approximately cylindrical 
shape, while with more than two points it is distorted in more 
than one direction into a dished shape or otherwise, which 
may permanently warp it beyond power of recovery. The 
reason is, because certain parts of the metal are then actually 
stretched while others remain normal. That this is true can 
be vividly demonstrated by merely bending a thick sheet of 
writing-paper, which does not hurt it, and then by pushing 
it a little way into one's hat, which ruins it. Practically, with 
thin metals this action may be neglected, and it is often best 
to put a high-point at each angle of the contour line of the 
blank, as, e.g., three in a triangular die, four in a square one, 
etc. These points entering into or over the other die first 
serve to guide their relative motion during the rest of the 
stroke, and thus to protect such parts of the cutting-edges as 
follow after into contact. 

For similar reasons it is obviously better to let the longest 
punches in an upper gang-die be located near the outer ends, 
as in Fig. 200, especially if the die is long in a lateral direc- 
tion; and the outer ones should strike the work at the same 
time. 

Deep Punching. 

In ordinary punching presses a rough limit to the thick- 
ness which can be worked cold is usually found for such 
metals as iron and mild steel in a dimension but little greater 
than the diameter of the punching. Beyond this there is 
apt to be trouble in the way of punches crushing themselves 



134 PRESS-WORKING OF METALS. 

down, or being torn apart in the act of stripping. If, how- 
ever, special precautions are taken in the way of very slow 
ram motion, so as to give the metal time to flow, and espe- 
cially in the way of guiding the punches all the way down, 
so that they cannot buckle (spring out of a right line), some 
remarkable results may be, and have been, obtained. The 
most curious specimen I have seen was made by Messrs. 
Hoopes & Townsend, of Philadelphia, and consists of a 
block of iron nearly 2" thick, with a T V 7 hole punched through 
it, cold, the bottom end of the hole being only about -fa" 
greater diameter than the top. I believe, however, that work 
even somewhat proportionately thicker than this has been 
punched. 

The " wads " from this thick work are much shorter than 
the hole. As their density is but little increased, it follows 
that some of the metal under the punch must flow sidewise 
into the walls surrounding the hole, thereby increasing the 
bulk of the object being punched. In holes of less length 
than their diameter, e.g., in boiler-work, this thinning of the 
blank or wad is noticeable, but to a much less degree. 

Punching Tapering Holes. 

In general, for thin metals, and particularly for paper, 
cloth, and such like materials, it is necessary that a punch 
should fit a die closely, so as to allow none of the material 
to creep down between. Indeed, a rule frequently used by 
the writer for accurately testing such dies has been to see 
that they would cut wet tissue-paper, cleanly, all around. 
In the practical punching of metals of some considerable 
thickness, however, say i" and over, it is customary to 
make the hole in the die larger than the punch, the object 
being to reduce the pressure upon said punch, thereby adding 
to its durability, and also to save some of the power required 
for the performance of its work. The result of such a con- 



CUTTING PROCESSES. 135 

struction is of course a conical, or other tapering, blank re- 
moved from the hole, its upper end being the diameter of 
the punch, and its lower end that of the die. It is obvious 
that this can be pushed out of a sheet or bar of metal more 
easily than would be the case if it were parallel, chiefly on 
account of the reduction of friction where the sides of the 
blank slide down against the walls of the hole — or, in common 
parlance, because it has better clearance. 

I have not at hand accurate records of the relative power 
required for different amounts of this clearance between 
punch and die, but I remember that in some interesting ex- 
periments made some years ago by Messrs. Wm. Sellers & 
Co. the minimum power was found to be required when 
the clearance amounted to \ of the thickness of the sheet 
being punched. When the blank was either more or less 
conical than this, the power had to be increased. As a matter 
of fact, however, such proportions represent an extreme case 
beyond that generally used in practice, where the clearance 
is generally not over from y 1 ^ to T ^ of the thickness. For 
instance, in punching f-" thick bars a l" punch will often 
be run with a die i T V' m diameter, which gives a ratio of T l Y . 
In general, the clearance in ordinary work will vary from 
? 1 T " to T \". In some cases, with round holes, the conical 
shape in question may perhaps happen to be an advantage, 
as when the large end can be turned outward in riveted joints, 
etc., but in other cases it may, on the contrary, happen to 
be detrimental. 

Imperfect Sheared Surfaces. 

In considering the question of whether to shear and 
punch a given piece of work, rather than to mill it and drill 
it perhaps, it must be remembered that sheared surfaces are 
necessarily rough and lacking in accuracy. More than this, 
the contiguous metal is somewhat disintegrated, having its 



I36 PRESS-WORKING OF METALS. 

fibers sent downward by the tearing away of the removed 
metal and the sliding past of the shear-blade or punch. 
This weakens its structure to such an extent that many 
modern boiler specifications insist upon all holes being reamed 
larger to remove the damaged wall of metal. Others allow 
no punching, but require drilling from the solid. 

Drifting or Re-punching. 

The word "drifting" is used in a number of different 
senses, but in press-work is usually applied to a system of 
what may be termed re-punching. This consists of enlarging 
a hole already punched, or possibly drilled, or even cast, 
by forcing a punch through it, to shave off the walls to a 
larger diameter. The operation is thus more nearly akin in 
principle to the action of a planing- or slotting-tool rather 
than to ordinary punching. The operation is a partial remedy 
for the evil mentioned in the last paragraph, inasmuch as it 
lightly shaves off the wall of disturbed metal. 

Sometimes a drifting-tool consists of an elongated bar. 
of the required cross-section to suit the shape of the hole, 
which is equipped with a succession of teeth, one above the 
other, its general form being slightly tapered so that as each 
set of teeth follow they will shave out a little more metal 
until the largest diameter is reached. A tool like this is 
usually dropped through the work when it has finished its 
stroke, to save time and to avoid any damage to the teeth 
that might occur by pulling it up again through the aperture 
that it has scraped out. Such an operation is sometimes 
called " broaching." In this book, however, the term will 
be reserved as appertaining to certain conditions of the proc- 
ess of drawing — to be mentioned further on. 

A Museum of Blanks. 

In Figs. 201 to 233, 235 to 250, and 255 to 260, all in- 
clusive, are shown top views of various blanks, each of which 



CUTTING PROCESSES. 



157 



has been cut from the sheet at one stroke of an ordinary 
pair of cutting-dies. They are mostly of such shapes as are 





237 



*M <£*f#lllll 

241 243 245 246 247 24 s- ■ M 

Hii . m -■■ 'so 




l r » • 2 58 25 9 

255256257 

Figs. 201-264. 



26 3 2^ 



produced in regular tinware factories, and consist chiefly of 
parts of "pots, kettles, and pans," together with shovels, 
table-plate, badges, etc. Figs. 251 to 254 show blanks 



I38 PRESS-WORKING OF METALS. 

that have been merely sheared apart from a rectangular sheet 
by a gang of curved shear-blades, thus producing at one 
blow the necessary pieces for a stovepipe-elbow. Such 
work as Figs. 234 and 261 is usually perforated in gang-dies, 
where a number of punches are set in an upper plate, as 
shown in Fig. 200, and where the lower die usually, but not 
always, consists of a single plate of steel containing proper 
holes for the punches to enter. The remaining pieces from 
Fig. 262 onward have been cut by the " successive " system. 

Gang-cutting. 

The mere grouping of dies and punches, as indicated in 
Fig. 200 and referred to in the last paragraph, the object 
generally being rapidity of work and uniformity of spacing, 
is so simple and obvious as to require but little mention. 
The process involved may be termed gang-cutting or gang- 
punching, according to circumstances. It is employed for 
making " perforated metal " so called, for rows of rivet-holes 
in boiler-sheets, for ornamental-work in brass and paper, etc., 
etc. The perforations as well as the spacing may of course 
be either alike or different. Sometimes all the holes required 
are punched at once, and in other cases one or more rows are 
produced at each stroke, the sheet being fed along intermit- 
tently — automatically or by hand. In some cases the sheet 
is the required product, in others the blanks. 

Combination-cutting. 

A common method of producing completed pieces at a 
single operation is by " combination-cutting" dies, wherein 
one or more male dies are usually set inside of a female die, 
and vice versa. The sexual terms just used have been 
before mentioned, and are generally understood as designating 
respectively any punch, such as [7, Fig. 197 — the male — 



CUTTING PROCESSES. 1 39 

which enters a die, and any die, such as L — the female — 
which is entered by a punch. 

In Fig. 265 is shown a typical form of combination dies 
of the kind referred to, which will produce any perforated 
work like Figs. 234, 261, or 264, at the same time cutting 
the outside contour. As shown, it is arranged for cutting 
simply a circular ring or washer, M. Such ring, of course, 
remains upon top of the lower die L, the small blank cut from 
it dropping through as usual. An inspection of the picture 
will show that L consists of a male die at the outside and a 
female die in the center, while U consists of a female die out- 
side and a male die in the center. The rings K K' are used 
as knockouts or strippers and are usually driven by springs, 
the function of K being to drive the finished ring out of the 
upper die and of K' to lift the surrounding remainder of the 
sheet from the lower die. The work is, of course, shoved out 
sidewise or backward, either by means of the surrounding 
sheet itself, or by means of gravity, when the press happens 
to be in an inclined position. Such dies as these are largely 
used for cutting armature disks and similar accurate work, 
oftentimes being built with a large number of teeth or notches 
around the outer edge, which obviously makes them very 
expensive. They are, however, usually built up in sections, 
so that if one piece needs repairing or renewing the whole die 
need not be thrown away. Sometimes dies of the kind just 
described are turned upside down from the position shown. 
The objection to this, however, is that the blanks from the 
perforations have to be driven upward through a hole or tube 
which usually curves over and delivers them at one side of the 
upper die, or of the ram, should they be pushed so far up. 

Successive Cutting. 

Fig. 262 illustrates a system of gang-punching used for 
producing washers like Fig. 264, and other perforated articles. 



14-0 PRESS-WORKING OF METALS. 

A pair of dies for such work are shown in Fig. 266, where 
the metal M, being fed in the direction of the arrow, is 
advanced to the point a at first stroke of the press so that the 
punch n will perforate it and drop through the punching or 
blank M' (or Fig. 263). It is then advanced to the point b, so 
that at the second stroke the punch u' will make the large hole 
around the small one. The pintle p, projecting below the same 
and set centrally therewith, enters the small hole and serves 
to guide the metal more accurately than would otherwise be 
done by ordinary gauging, so that a completed washer M" (or 
Fig. 264) drops through the lower die L. At the same time 
the punch // is punching a second hole and dropping through 
another blank M\ which again is advanced at the next stroke 
to have another washer punched from around it, etc. Thus 
is produced a complete piece of work at each stroke, except 
the first and last at the respective ends of the bar or sheet. 
This method can of course be amplified so as to punch any 
number of holes, of any shape, and in any relative position, 
at the first stroke, and then, at subsequent strokes, to punch 
around each one separately, or around or between any of them 
or any groups of them that may be desired. In this way are 
cheaply produced many small articles, such as keys, parts of 
locks, etc. 

Successive Gang-cutting. 

In making ordinary gang-punching dies for producing 
work, or rather scrap, of the general character shown in Figs. 
261, 267, and 269, it is evident that in some cases the holes 
might be so near together that the little isthmuses, as we may 
call them, i, i, i, etc., would be too narrow (so as to avoid waste 
of metal) in the female die to secure the requisite strength for 
it to hold together. The remedy in such case is to so set 
the gang of punches and corresponding holes in the lower die 
that certain alternating holes may be punched in the metal, 



CUTTING PROCESSES. 



141 



u 


■ 

Wm 




wm 

mir ; 


mm 


>//, 



L 





© no \ 



Fig. 265. 



Fig. 266. 




Fig. 267. 



Fig. 268. 




B C 



000OO 
000OO 




B C 



O 

o 



o 
o 



Fig. 269. 



Fig. 270. 



H 2 PRESS-WORKING OF METALS. 

omitting the ones between, as for instance in Fig. 267, where 
those marked A are thus punched first. This diagram repre- 
sents a sheet of tin-plate from which six fruit-can tops have 
been made in gang combination cutting-forming dies. The 
lower die is shown in top view in Fig. 268. After the first 
stroke the sheet is either turned around or turned over so that 
at the second stroke all those holes marked B will be punched, 
and so on. In feeding a long strip of metal by this system 
(see Fig. 269), there is no lost time except at the ends of the 
strip, where, for instance, in the case shown, only two holes, 
A A, could be punched at the first stroke, two whole ones 
and three halves, B B, etc., at the second stroke, but the five 
complete ones, C C, etc., as located in the lower die, Fig. 270, 
at the third and subsequent strokes. 

A great deal of work is done upon this system in brass- 
factories and other places producing small articles from long 
rolls of metals, the feeding usually being automatic. It is a 
curious fact that this principle of interspacing dies has recently 
become the subject of a patent, which, of course, is an ab- 
surdity, as the system is very old. 

Cutting Die Qualifications. 

In general, some of the important points desirable to 
secure in cutting dies are first-rate material of proper hard- 
ness; great rigidity against distortion by springiness, espe- 
cially in lateral directions; and durability, by having ample 
length of bearing-surfaces, as from w to x and y to z, in Fig, 
197. Each die between these points should be perfectly 
parallel, so that when sharpened by grinding off the top sur- 
face of L and the bottom surface of U they will still fit each 
other as tightly as at first, or as nearly so as is consistent with 
what their cylindrical or prismatic surfaces, as the case may 
be, which slide against each other, have actually worn away. 
It is, therefore, very bad practice to make the hole in a round. 



CUTTING PROCESSES. 143 

lower die conical all the way through and to make the upper 
die conical, decreasing from the bottom upward. Such dies 
will work well at first, but have very little " life," whereas if 
made as in Fig. 197 they can be ground away gradually (upon 
their horizontal surfaces) to the points w and z, as shown by 
the dotted lines. Below s it is necessary to have the size of 
the hole somewhat increased to give clearance to the blank, 
that it may not clog therein. Sometimes this is made conical, 
as shown, and sometimes it is enlarged bodily and left parallel, 
with a small step at z. It is well, however, to have this 
clearance quite small. On ordinary dies about 2 inches thick 
it has been found good practice to make the clearance-distance 
a from ■£$ to ^ inch. In the upper die there is no need of 
giving any clearance, and some die-makers even go so far as 
to make U slightly larger at the top, so that as the lower sur- 
face is ground off the bottom diameter is slightly increased, 
thus maintaining a tighter fit in the lower die than would 
otherwise be the case. It is generally easier, however, to 
make the sides parallel all the way up. 

Hardness of Dies. 

While in the case of punching and shearing thick metals 
the upper and lower dies or shear-blades, as the case may be, 
are both made hard, there is a large variety of work where 
one of the dies is made moderately soft, the other one being 
as hard as possible, consistently with not having the sharp 
edges crack off in working. Such dies can usually be worked 
upon all metals no harder than iron or very mild steel which 
are less than T V inch thick. The object is that the dies may 
be quickly and cheaply repaired, as far as maintaining sharp 
cutting-edges is concerned, by hammering up the top or bot- 
tom surface, as the case may be, of the soft die, thus spread- 
ing out or riveting such die sidewise, making it larger if it be 
the male, and smaller if itbe the female. This can often be 



144 PRESS-WORKING OF METALS. 

done without unsetting either of them from the press. After 
the proper amount of hammering the dies are oiled and forced 
together, the hard one shaving or drifting off the surplus 
metal from the soft one, thus leaving them again a good fit, 
one within the other. It is, of course, necessary that the 
hard die should in such case have a reasonably sharp edge. In 
most instances it is best to have it freshly ground. The grind- 
ing should, obviously, be done on the bottom of an upper 
and the top of a lower die — not upon the sides where the 
size would be affected. 

The vexed question of which die shall be hard — male or 
female — is not of very much consequence, although many 
people take it for granted that it should be the female, simply 
because they have always been accustomed to that method. 
One good reason exists for this, however, viz., the presence 
of a hard surface, which will not wear away so fast, over 
which to slide the sheets, these sometimes being covered with 
scale, and therefore doing a good deal of grinding on their 
own account. Under some conditions, where great accuracy 
of shape and size is required, it is difficult to make the female 
die hard, because of the trouble of grinding it out to exact 
dimensions after hardening, ordinary grinding-machinery not 
being made for sliding through small holes of irregular shapes. 
If, on the other hand, the male die is hard, it usually can be 
ground exactly as wanted, because such grinding is on the 
outside, where accessible. The reason for such after-grinding 
being necessary is, of course, the warping or shrinking, or 
both, of the steel, which often happens after hardening to an 
extent great enough to spoil the accuracy with which the die 
was originally made. The difficulty of grinding above spoken 
of obviously does not occur with round and elliptical dies, as 
the female ones can be ground out inside in ordinary grind- 
ing-lathes, using common and " oval " chucks respectively. 



cutting processes. 145 

Bevels of Cutting Edges. 

The bevel of shear-blades has been already referred to as 
being usually about 75 °. This angle, of course, appears in 
cutting dies, as A and A', Fig. 197. Its object is chiefly to 
facilitate the grinding and hammering-up practiced in repairs, 
although it is supposed that the metal is cut easier, with a 
little less power, than when the edges are at an angle of 90 , 
as in Fig. 187. Just how much power is saved thereby I 
have at present no data regarding. In some cases, however, 
it is better to make the surface of dies perfectly flat, with a 
90 angle, to avoid the little notch that is left in the work, 
as shown at n n, Fig. 190, or the analogous bevel occurring 
when the dies are sharp. 

Strippers, Hold-downs, etc. 

It is usually necessary to supply a male cutting-die with a 
"stripper," which in general consists of a stationary ring 
surrounding it and extending slightly below it when in upper 
position, as shown at S, Fig. 199. This is usually secured 
either to the press-frame back of the ram or to the lower die 
or bolster, it being bent downwardly in such case to meet the 
place of fastening. The latter method serves a good purpose 
where the downwardly-extending portion is not in the way of 
the sheet, as for instance where the sheets are narrow. If, 
however, it is desirable to move the sheet back a considerable 
distance, as for cutting another row of holes forward of the 
first row, etc., a stripper is apt to be in the way if mounted 
as last mentioned. Sometimes a stripper is a ring sliding 
upon the male die and driven down by springs abutting there - 
against. In still other cases it slides in this way, but is 
struck upon the up-stroke by stationary abutments fastened 
to the press-frame. 

The stripper shown in Fig. 196 gets its adjustment by 



I46 FEESS-WORKING GF METALS. 

swinging upon a pivot and does not therefore always main- 
tain its lower surface in a horizontal plane. This feature en- 
dangers small, slim punches by " cramping" them when the 
metal tries to tip into a different position from that in which 
it was punched during the process of " stripping " — that is, 
having the punch pulled out of it. Such a stripper, how- 
ever, serves a good purpose for heavy work. An alternative 
device, which does not cramp, is made to slide vertically up 
and down to attain its adjustment. 

When work is punched without any stripper at all it is gen- 
erally the case that the punch is tangent to the edge of the 
sheet at one or more points — thus allowing the scrap sur- 
rounding it to spring away, or partly fall away in pieces, so 
as to relieve itself and slip off. This method is often prac- 
ticed with tin-plate and other thin metals. 

A "hold-down" is apparently of the same nature as a 
stripper, but is used in connection with a shear-blade rather 
than a punch, and for a different purpose. Its function is to 
keep that part of the work from tipping-up which rests upon 
the lower blade, during the down stroke of the upper blade as 
it cuts off and pushes down the severed portion. It usually 
consists of a fixed bar extending across and immediately above 
the work a few inches from the upper blade. Did it appear 
in Fig. 187, it would be located at the right side of the pict- 
ure a little above and to the left of the points. It is not 
needed in cutting off long bars where their own weight, sup- 
plemented perhaps by the pressure of the operator's hand, 
acts with sufficient leverage to keep them down. Obviously 
this device is more necessary with dull blades (as in Fig. 189) 
than with sharp ones. 

Analogous to an ordinary hold-down is the "clamping- 
pad " used on some shearing-machines, especially for slitting 
large sheets. This consists of a stiff bar lying against the 
face of the upper blade and over the lower one, having the 



CUTTING PROCESSES. 147 

same length as the blades themselves. It is automatically- 
operated by cams or springs so as to firmly clamp down the 
sheet just before the shearing commences and release it as soon 
as, or before, the ram gets up, so that it may be slid to 
another position or removed altogether. This pad is fre- 
quently mounted upon the ram — sliding up and down there- 
on. Its function is not only to keep the work from sliding 
out of place, but to prevent its being warped and bent by the 
action of the blades. 

A ring- or disk-shaped pad is often used in certain cutting 
and forming dies — for similar reasons to the above — also, in 
some cases, to prevent " buckling," where metal is forced 
downward and inward, edgewise upon itself, so to say. 

Die-gauges. 

In regard to gauges, they are too numerous in design to 
be described in detail here. In their simplest form they are 
merely round pins, projecting upward from the lower die, as 
at G, G' ', Fig. 199, for back-gauges, and G" for an end- 
gauge, so called. Sometimes, however, gauges are so ar- 
ranged as to confine a strip of metal at both front and back, 
and in many cases the end-gauge G is arranged as a "fin- 
ger-gauge," so that it will move up and down automatically 
by the action of the press at the proper time. When the 
feeding and gauging is done by hand, however, the work is 
lifted so as to slide over the top of G" . The "pin" of a 
finger-gauge is sometimes arranged to project downward into 
the work from above. 

Cutting Speeds. 

In regard to the best speed for running cutting dies, but 
little has been accurately determined. The ordinary quick- 
running presses in common use, making from 50 to 200 strokes 
per minute and generally averaging perhaps 100, seem to 



I48 PRESS-WORKING OF METALS. 

work well for shearing and punching most of the common 
metals which are not over | inch thick. An exception, how- 
ever, should be made for cast steel, for cutting which a press 
should be geared so as to run very much slower than for mild 
steel, iron, brass, and the softer metals. The reason for this 
is simply to get more durability in the dies, as the edges seem 
to get dull very rapidly at quick speeds. For punching 
metals over \ inch thick it is usually better to use what is 
known as a geared press, which generally makes from 25 to 75 
strokes per minute. In the cases mentioned presses of short 
stroke, usually 2 inches or less, are referred to. Where a 
press happens to have a much longer stroke, it is of course 
necessary to run at a lower number of strokes per minute to 
secure the same actual cutting speed. This, from the above 
figures, will average from 8 to 60 feet per minute, which com- 
pares closely with the speeds used for the shaving or paring 
processes of the machine-shop. 

Cutting Pressures. 

In regard to the pressure required for chiseling operations 
no data are at hand. It must, however, be considerably 
greater than in shearing and punching, for which it may be 
said in general that the actual force required to shear a given 
unit of section is somewhat less than that required to pull 
apart the same section by stretching — that is to say, in most 
of the ordinary ductile metals, such as steel, iron, brass, 
copper, etc. In other words, the ultimate shearing strength 
of these metals is a little less than their ultimate tensile 
strength, sometimes (as observed with certain steels) being 
only about 75 per cent, thereof. 

This is assuming sharp cutting edges, however, which are 
not always present. Considering the fact that cutting tools 
are often dull, a safe general rule in providing a press for 
doing certain shearing or punching work would be to have it 



CUTTING PROCESSES. 149 

capable of safely exerting and resisting a force powerful enough 
to tear apart 1 square inch of section of the particular metal 
to be used for each square inch which is required to be 
sheared. In the case of mild steel this may be considered 
roughly as about 60,000 pounds per square inch; for wrought 
iron, 50,000; for bronze, 40,000; for soft brass, and copper 
and cast iron, 30,000; for aluminum, 20,000; for zinc, 10,- 
OOO; for tin and lead, 5,000; etc. — always reckoning in the 
same way, according to their tensile strength, which may 
generally be found in any engineering reference book — that 
is to say, in cases where the author of the book has taken the 
trouble to mention the particular metal which the reader hap- 
pens to want, which is not always. 

Unfortunately these books, even the best of them, do not 
give full tables of the shearing-strengths of the ordinary 
metals. The writer has in view the publication at a future 
time of some definite information in this line which he hopes 
to obtain from operations in actual presses with actual dies, by 
means of a special weighing-apparatus of his own contrivance. 

To give an example of the principle above stated : Sup- 
posing a press-user wishes to shear off bars of iron 1 inch 
square, or bars 2 inches by \ inch, or 4 inches by \ inch, or 
to punch a hole I inch in diameter (which is about three 
inches round) in iron \ inch thick, or 2 inches diameter in a 
sheet 1 inch thick, or 12 inches diameter in a sheet ■£$ inch 
thick. In any of these cases he will want to cut an actual 
section of about 1 square inch. He will, therefore, need to 
use a machine which will give 50,000 pounds pressure at the 
beginning of the cutting operation, or, more accurately speak- 
ing, a little after its beginning, when some slight crushing of 
the metal has taken place. This initial pressure, for instance 
in the case of cutting off a bar 1 inch square, will not have 
to be maintained during the whole 1 inch of ram descent 
while the cutting is going on. This is because the resistance 



ISO 



PRESS-WORKING OF METALS. 



will soon begin to decrease, probably after the first f inch or 
\ inch of descending, ceasing entirely after about f inch of 
motion, as at this time the bar will have been so disintegrated 
as to fall apart before being pushed entirely down to the 
amount of its own thickness. 

The maximum pressure necessary, therefore, for shearing 
proper is measured by the amount of cross-section to be cut, 
and may be formulated thus: Taking P = pressure in pounds 
required from ram, IV = width and T= thickness in inches 
of bar to be sheared off, and 5 = shearing strength per square 
inch in pounds of the material of the bar, we have : W T = 
area of section cut and S WT= total initial pressure. 

Hence P = 5 W T, that is, providing there is no dip to 
the blades. 

Applying this rule to punching, we let W — circumfer- 
ence, or length of contour line, of the hole, which is really 
the width to be sheared. For round holes, taking D = diam- 
eter in inches, we have W= Da (or 3.14 times D). For 
square holes, taking D'= short diameter, we have W=4D f . 
As before stated, a rule easily remembered and one that is on 
the safe side is to let 5 = 50,000 for iron and tin-plate. 

The rule just given must, of course, be modified in favor 
of less pressure requirement wherever it is practicable to use 
dip upon one of the blades or dies. Figs. 271, 272 and 273 




f w 1 

Fig. 271. Fig. 272. Fig 273. , 

show successive stages of the descent of an upper blade, U, 
upon a bar of metal, M. In the first position it will be seen 
that the practical width of cut W is only about one half that 
of the bar, while in the second it has become equal to the 
whole width of the bar, and this is evidently the maximum 



CUTTING PROCESSES. 



151 



width upon which it will act. The average thickness, how- 
ever, in this position is but one half that of the bar, and the 
area of metal yet to be cut is measured by the triangle just 
below the blade, which is evidently but one half the area of 
the bar's cross section. In the last position the width of cut 
has been reduced. From these diagrams it will be seen that 
a blade that has as much dip as that shown will require only 
about one half the pressure required by a blade without dip, 
and this is nearly correct, except that some excess would be 
required to bend and twist the bar, as in Fig. 195. In Fig. 
274 is shown a bar twice as thick as before, and it is here evi- 
dent that when the width of cut has reached that of the bar 
itself there remains about three quarters of the area yet to be 
cut. Consequently the pressure is reduced by the dip some- 
thing less than one quarter only. In Fig. 275 is shown the 





opposite extreme, where only about one half the width of the 
bar and one half the thickness are at the same time being con- 
tributed as factors to the area being sheared. Consequently 
the pressure required is only a little more than one quarter of 
what it would be with a dipless blade. In Fig. 276 is shown 




Fig 276. 

a gang of punches, a, b, c, d — a having just reached through 
the bar of metal M when b is ready to commence. In the 
same way b will reach through when c commences, etc. Thus 



152 PRESS-WORKING OF METALS. 

it is obvious that the pressure required at arry time is only that 
due to the resistance of one punch, but that the whole height 
traveled by the ram while doing its work is represented 
by h, which is four times the thickness of M, or, in general, 
as many times its thickness as there are punches, providing 
they are set with this amount of dip. An analysis of the 
preceding diagrams will show that the same rule holds good — 
viz., that the maximum pressure required is approximately 
in inverse proportion to the working distance traveled by the 
ram. 

In estimating, therefore, the necessary pressure for any 
given pair of dies, the pressure required for flat dies without 
dip should first be ascertained by the formula given above, and 
then a reduction should be made in proportion to the increase 
of time during which the dies a/e doing their work over that 
due to the thickness of the metal itself, as caused by the par- 
ticular amount of dip that may be present in the dies. 

The pressure data given assume an upper die or punch of 
the same diameter as the die which it enters, such construc- 
tion Insuring a parallel hole through the metal. When the 
clearance referred to in a previous paragraph is present the 
pressure-coefficient is really a little less, but hardly to an ex- 
tent worth considering. 

The punching pressure required is also somewhat lessened 
when holes are located very near the edge of a sheet or bar, 
on account of the spreading of the metal sidewise, but this 
does not amount to much in practice, and such punching 
should be avoided. 

Regarding the pressure required for stripping metal from a 
punch during its ascending stroke, I have no reliable data at 
hand. It varies considerably with the amount of punch and 
die clearance, the smoothness of the punch and the squareness 
of the stripper therewith, together with its rigidity, etc. It 
is undoubtedly a good deal less than one tenth of the punch- 



CUTTING PROCESSES. I S3 

ing pressure, even in extreme cases. A series of experiments 
in this direction are certainly very desirable, and the writer 
hopes upon some future occasion to be able to publish an ex- 
perience of this kind which he has not yet enjoyed. 

Adaptation of Presses. 

Regarding the kinds of presses used for the cutting pro- 
cesses which have been described in this chapter, it may be 
said that, like the Scotchman's whiskey, there are no bad 
kinds. In other words, almost any sort of a press is some- 
times suitable — the nearest approach to an exception to this 
statement being perhaps the drop press tribe, whose members 
are generally employed in other work. Furthermore, their 
rams are apt to be so loosely fitted to their columns as to en- 
danger the cutting edges of delicate dies. This, however, is 
not necessarily the case. A more serious objection would 
usually be the abnormally high speed attained by the ram at 
the bottom of its stroke — due to acceleration by gravity. 



154 



PRESS-WORKING OF METALS. 



CHAPTER VII. 



BENDING PROCESSES. 



Bending. 

FOLLOWING a natural order, we come next to forming or 
bending processes, where the metal has its surfaces pushed out 
of their original planes into some new shape, but where the 
thickness is supposed to be not materially altered, except 
where it is incidentally made thinner in certain spots by being 
stretched, etc. In Fig. 277 is shown a V-shaped pair of bend- 







1 1 ' 






Fig. 277. 



Fig 278 



ing dies and beneath them a straight plate of metal, a, to- 
gether with the same as it appears after bending, at b. The 
dotted line b' shows where the dies tried to bend it, and the 
black line b its final position as assumed by its own elasticity. 
This, of course, varies with the material, a piece of lead or 
even copper remaining very nearly in the same shape as the 



BENDING PROCESSES. 1 55 

die which forms it, while iron, mild steel, hard brass, etc., in 
the order named, require such a die to be of a more and more 
acute angle, as the metal approaches nearer the character of a 
spring. 

In Fig. 278 is shown a pair of bending or forming dies 
which are removed one step further from the simplicity of the 
first named, giving two bends to the work instead of one. 
Here the same difficulty occurs in regard to the edges spring- 
ing part-way toward their original shape after leaving the 
die, as shown again by the lines b b. It is not therefore 
possible with a die of this kind to produce edges which are ex- 
actly square with the main body of the plate. An approxi- 
mation may, however, be sometimes made by bulging upward 
the horizontal surfaces of the dies, as shown by the dotted 
lines in Fig. 278, to an extent not greater than is suited to 
the elastic limit of the particular pieces of metal used. The 
die therefore attempts to make the work somewhat concave 
upon the bottom, as at c, which forms the corners at a suffi- 
ciently acute angle to approximately counterbalance the ten- 
dency to spring open ; so that when the bottom has sprung 
back flat the edges will stand up perhaps nearly enough at 
right angles thereto. To place practical dependence upon 
this system, however, requires uniform blows by the press 
and uniform elasticity in the metal. 

Forming. 

In Fig. 279 is shown a pair of round forming dies, where a 
flat circular blank, a, is laid in the recess m, which acts as a 
gauge merely for locating it centrally. It is then pushed by 
the upper die, or punch, U, through the parallel opening n, 
and falls beneath the dies — being stripped off the punch when 
the same is ascending by the sharp " stripping-edge " o. At 
b is shewn the shape of the work when in a half-way stage of 
the operation, its final condition being as at c. With dies of 



i$6 



PRESS-WORKING OF METALS. 



this kind the edge of the work cannot be very deep in propor- 
tion to its diameter, on account of the wrinkles which evi- 
dently attempt to form when the circumference is reduced. 
It is true that these incipient wrinkles can be somewhat 
smoothed out by allowing the punch and die to fit tightly 



J 


■ 








.._. 




mm l 



Zl 




~\: 



lllllllll'l 



L 



~3 C 



Tzz3uiir 

c c- 



Fig. 279. Fig. 280. 

enough to confine the metal to its original thickness — provid- 
ing this thickness came uniform, which it usually does not in 
practice. In doing this, however, the metal of the edge is 
lengthened in certain spots in a vertical direction, which causes 
a jagged edge. If the depth is too much increased, the wrinkles 
so fold upon one another as to tear the metal entirely away at 
certain places. The remedy for this will be considered later 
on under the head of the drawing process. With metal like 
ordinary tin-plate, in diameters of not less than 2 inches, a 
width of edge from -g- to ^ inch can usually be obtained in plain 
forming dies without objectionable wrinkles. 

With cylindrical work like that in question, and also with 
elliptical work (which resembles it by having a convex con- 
tour with an edge extending all around), the outward springing 
of this edge does not occur to an objectionable degree, as it 



BENDING PROCESSES. 



iS7 



does with rectangular work having two separate and uncon- 
nected edges, like that shown in Fig. 278. This is because 
the edge c forms itself into a hoop, as it were, to confine itself 
from moving outwardly, which it cannot do when released from 
the die without actually stretching in a circumferential direc- 
tion ; and this evidently can occur but in a very slight degree. 
In Fig. 280 is shown a pair of forming dies for turning an 
edge upon an internal, instead of an external, circular contour. 
These take a perforated blank, a, and open out the hole, turn- 
ing it downward into a cylindrical-shaped edge, as at b. If 
an attempt is made to get this edge too wide, certain cracks 
will appear, as at cc, etc., in the pieture. As the edge in 
opening outwardly increases its circumference, it will not stand 
more than a certain amount of tensile strain, the stress here 
being of exactly an opposite character to the compressive one 
which forms the wrinkles in work like that in Fig. 279. 



Embossing. 

In Fig. 281 is shown one type of a pair of embossing dies, 
so called. The word " embossing" is used in this treatise, 
and very generally in the sheet-metal trades, to denote a small 
degree of forming or bending at various points upon the sur- 
face of a piece of sheet-metal, the location of which usually 
tends to show in top view a figure or 
design of some kind, decorative or 
otherwise, as, for instance, pictures, 
symbols, lettered inscriptions, etc. In 
such work the metal is pushed down- 
ward or upward more or less at various 
points into ridges and grooves, but 
not to a sufficient extent to tear it 
apart. The tendency is evidently to 
so tear it, as its outer edges are 



U 



1 



Fig. 281. 
maintaining a rigid resistance against inward flow (except in 



i 5 8 



PRESS-WORKING OF METALS. 



certain forms of the drawing process), and the metal has there- 
fore to elongate where forced to take a shape whose cross-sec- 
tion shows a longer profile-line. This is shown by the section 
of the piece of embossed work, b, which is longer in profile 
than is the blank from which it was made, a. In the case 
given I have represented a pair of circular dies with two annu- 
lar grooves sunk in L, corresponding ridges projecting from 
U. This is a design sometimes used upon the heads of tin 
cans, etc., its object being partly to make them stiffer, and 
perhaps partly for ornament. Such embossing, however, is- 
merely typical of an infinite number of designs which may be 
thus stamped upon ductile metal. The word embossing, as 
applied to this process, should not be confounded with the 
same term as sometimes used to designate the process known 
more properly as coining, to be described further on. 

In Fig. 282 is shown a broken-away vertical section of one 
groove and ridge of a pair of embossing-dies, where the flat 
surfaces have approached each other within a distance meas- 
ured by the thickness of the metal, represented by m. Theo- 
retically the space between upper and lower die might properly 





P 

Fig. 282. Fig. 283. 

be this thickness, m, at the points n, o, and p, as the metal 
would then exactly fill between at all points. Practically, 
however, it is better to give an embossing-die clearance at 
such points as n and o, letting the metal follow the "tight 
points " to suit itself, as in the picture. This is desirable, be- 
cause some of the metal may be a little too thick, or dirt may 



BENDING PROCESSES. I 5 9 

accumulate in the dies, in either of which cases there would 
be a jam between the points n and o, which would prevent the 
dies coming down home, or which, at any rate, would require 
a great deal more pressure to do the work. Another reason 
for this clearance is the practical difficulty of the die-maker 
being perfectly sure that there is space enough everywhere, 
unless he follows the method here given, of being sure there 
is enough by having too much. It is customary to give a little 
clearance at/ also, but this is not of so much importance, as 
contact at that point would simply prevent the flat surfaces 
from coming together quite so tight. 

A simple method devised by the writer, and long practiced 
by those working under his instructions, for ascertaining the 
clearance of forming and embossing dies is to lay pieces of 
small lead wire, whose diameter may be about two times m, 
across the dies at the various points requiring a test. Between 
these points small pieces of the sheet-metal to be used, whose 
thickness is m, are laid upon the lower die to act as blocking, 
so that the proper stopping-point of the upper die may be in- 
sured. The press ram is then brought hard down, with the 
result of the lead being smashed out to the varying thicknesses 
represented by the spacing of the dies, and as shown in Fig. 
283. It is evident that all such points as n and o ought to be 
thicker than m, and this is generally easily determined by the 
eye. Such points as/ must, of course, never be less than m y 
and may be a little more. 

Cutting-Forming-Embossing. 

Almost all the various processes of forming and embossing 
may be combined with cutting, and with each other, wher- 
ever the work is of suitable shape. The tools for conducting 
such operations are usually called "combination dies," al- 
though the term is not very definite, being sometimes used, 
as before described, for the combining of two or more sets of. 



i6o 



PRESS-WORKING OF METALS. 



cutting-edges. 



K i 7 ~1 




& c 



In Fig. 284 is shown, in vertical axial sec- 
tion, a pair of combination-dies such 
as are very extensively used for pro- 
ducing fruit-can "tops," as shown 
in section at a, and "bottoms," as 
shown with embossed groove at a' or 
plain at a" . In practice these dies 
are assembled in separate pieces to 
some extent, to insure cheapness, 
durability, and facility of repairs, 
but they are here depicted in con- 
ventional form. It will be seen that 






Fig. 284. 

the outer cutting die has the female at the bottom as well as 
the inner one, a result which was not obtained in Fig. 265, 
Chapter VI, where the work remained flat. In this case the 
latter part of the upper die's descent cuts the central hole 
while the forming of the edge at b and the embossing of the 
groove at c is taking place. It will be noticed that the turn- 
ing upward of the inner wall of this groove causes a tendency 
to crack, as in b, Fig. 280, although in practice it is not made 
deep enough to produce this effect. Such action does not 
take place in a', because the stretching action is resisted by 
the continuous surface in the center, which is retained in the 
case of this can-bottom by removing the central cutting-punch 
d from the upper die. Should a plain flat bottom be desired, 
as at a ,r , the embossing-punch e is also removed. 

Sometimes combination cutting-forming, etc., is done in a 
double-action press with dies similar to the drawing-dies to be 
described in Chapter IX, Figs. 331 and 343. These dies 
have the advantage of strong and simple construction, and, in 
operation, of dropping the work through beneath the lower 
die. 



BENDING PROCESSES. 



161 



Knockouts. 

A knockout-ring is shown in Fig. 284 in the upper die at 
K, and in the lower die at K' . They are unnaturally given 
in closed position (as they would be were the dies shut to- 
gether) merely to show better the general contour of the sec- 
tional view. Sometimes what is called an " edge knockout" 
is used instead of the construction shown at K' , consisting of 
a thin ring rising in the groove K" and pushing against the 
edge of the work rather than underneath its flat surface. This 
ring at K", if driven up by strong springs, acts in some de- 
gree as a spring-drawing attachment (to be described later 
on), and serves to smooth out the slight wrinkles which usually 
otherwise appear in the edge of the work. The knockouts de- 
scribed are generally driven by springs, but sometimes by pins 
extending through the dies and attached to or pushed by 
certain positive-action knockout devices. In some cases such 
special knockout ''attachments" to a press are not positively 
driven, but are actuated by a strong spiral spring, or a spring 
made of rubber disks, etc. 

Speed and Pressure. 

The speed at which forming- and embossing-work is done 
is of little consequence, as in practice the ram speeds of the 
presses in common use are none of them fast enough to tear 
the metal by moving it more rapidly than its molecular inertia 
will permit. 

The pressure required for the processes above described 
varies too greatly to be formulated in a general way, being de- 
pendent upon the character of the work and the condition of 
the dies. For given pieces of metal, however, it frequently 
happens to be a good deal more than for the cutting operations 
performed upon the same. When the dies are so set as to 
actually squeeze the metal thinner, it is forced to flow sidewise, 
and a " coining " action is set up. In such case the required 



1 62 PRESS-WORKING OF METALS. 

pressure is very great, often exceeding the crushing strength 
of the metal. This, in its turn, is usually something greater 
per square inch of section than is the tensile strength. 

Assembling. 
Analogous to forming processes proper are various opera- 
tions where the assembling of two or more pieces is done, 
oftentimes upon the same general principle as the riveting 
down of an eyelet, or a rivet, which has been passed through 
two pieces of paper or metal. In general, some piece of metal 
which has previously been brought to shape by dies or other- 
wise is driven tightly, or perhaps dropped loosely, into or 
onto some other piece or pieces, whereupon they are all fas- 
tened together by some auxiliary forming process which 
bends or forms certain edges or surfaces in a manner best 
adapted to locking the various parts permanently together. 

In this way two cup-shaped pieces are connected to form a 
certain style of door-knob ; ornamental stamped-out parts are 
assembled into the stem of a gas-fixture; and the base- piece 
is fastened onto a cuspidor or coal-scuttle. Such work will 
be further set forth in the next chapter, under the head of 
curling, etc. 

Involuntary Processes. 
In addition to the humanly invented processes we have been 
considering there are sometimes developed others which, to 
a careless observer, might seem to emanate from the brain and 
hand of his Satanic Majesty. Among what may thus be called 
involuntary processes is the very annoying one known as warp- 
ing, which occurs especially in the products of embossing and 
forming dies, as well as to some extent in drawn-work also. 
The most favorable conditions for its occurrence are thin 
metals, large diameters, and edges so shallow as not to form 
stiff trusses in themselves. The die-maker is often blamed 
for work thus coming from the press twisted and sprung, so 



BENDING PROCESSES. 1 63 

that it is impossible to make it lie flat upon a plane surface. 
Generally, however, a result of this kind is entirely owing to 
its design ; and Dame Nature, rather than the die-maker, 
must be blamed for one of the most provoking and perplexing 
problems which the die-user is called upon to solve. 

Mechanically, the cause of this warping is due to the middle 
of the stamped sheet of metal being too small for the outside 
thereof, so to speak. This occurs when the central parts have 
been embossed or otherwise drawn together and put under a 
tensile strain, while the average circumference of an outer 
zone, near the edges, has not been correspondingly reduced, 
and therefore does not assume the shortest distance around its 
course, which would naturally lie in a plane. A remedy is 
sometimes found by altering the design so that this outer zone 
may have various ribs and corrugations running approximately 
in a radial direction toward the center, such corrugations tend- 
ing to take up the surplus metal in a circumferential direction. 
These additional features can often be added by a judicious 
designer in a way to serve a decorative purpose. A similar 
warped effect can obviously be produced by letting the middle 
of the metal alone and stretching or otherwise increasing too 
much the area near the edges. This is often done by form- 
ing-dies when turning a narrow vertical edge around a large 
thin blank. Such action is due to imperfect "upsetting" 
where the circumference is reduced, and perhaps also to a too 
tight squeezing of the edge between the dies, which has a 
stretching effect. 

The converse of the conditions above mentioned occurs 
when the middle part of the sheet is too big for the outside, 
as is the case in any dished or saucer-shaped work. This is 
often seen in the bottoms of buckets, etc., which have been 
somewhat bulged, and which can be "flopped" back and 
forth, always staying in a position at either side of the plane 
of the outer zone of the metal. In such case the said outer 



164 PRESS-WORKING OF METALS. 

zone is pushed outwardly by the central parts, and is there- 
fore in a taut condition, which tends to make it stay flat rather 
than otherwise. If that surpassingly skillful artisan known as 
the "saw-maker" were to tackle a sheet of this kind, he 
w r ould soon flatten it by hammering it near the edges. If, on 
the contrary, he hammered it in the middle, it would be on 
account of converse conditions. 

Soft Punches. 

Forming work, especially in drop presses, is sometimes 
performed by using a punch made of soft and easily fusible 
metal like lead, or, preferably, a mixture of lead and tin, in 
proportion of about two of the former to one of the latter. 
The object in making such a punch in this way, is: 1st, 
cheapness, because it can be cast directly into the die, which 
is usually of harder metal, and of more expensive construc- 
tion ; 2d, a soft punch of this sort under the influence of a 
quick and powerful blow will maintain its shape by reason of 
its particles flowing by their own momentum, in whatever 
direction they can go to perfectly fill the die, or rather the 
interior of the work, which is supposed to be a slightly smaller 
copy of the same. If, therefore, the punch moves down 
quickly enough (as is usually the case in a drop-press), it will 
flow out and fill the interstices of a somewhat intricate die, 
as, for instance, in the case of ornamental brass-work in de- 
signs of imitation carving, etc. 

In drop press work these punches are sometimes used for 
thin metals, as in making dish-pans, wash-bowls, sauce-pans, 
etc. ; though formerly they were employed, before the advent 
of the drawing-press, very much more than now. In such dies 
a good many successive operations are necessary, that the work 
may be coaxed down, so to speak, a little at a time. It is 
then easy to cast a punch part-way down in the die for the 



BENDING PROCESSES. 165 

first operation, and after running through a batch of work 
tear it off and remelt it, to pour another one a little deeper, 
and so on. Thus a batch of pans can be run through over 
and over again, the die never being removed from its position. 
The punches are cast blocked off at part depth by laying a 
diaphragm in the die part-way down, or by using one of the 
unfinished pans itself for the purpose. The press ram has, of 
course, a proper " anchorage, " so to speak, to which the soft 
cast metal will cling. 

Fluid Punches. 

A rather curious modification of forming a deep article to 
shape by a punch entering a die is to make the former of 
water or other liquid. In other words, the idea is to force 
the work outward and down into the form of the die by 
means of hydraulic pressure inside of the same, proper ar- 
rangements of course being made for packing around the 
edges of the dies so that the fluid cannot escape. This sys- 
tem is chiefly used for comparatively soft metals, such as 
silver, britannia-metal, and other materials used for table-plate 
and analogous constructions. It is generally applied to a cup- 
like article which has already been brought nearly to shape in 
a drawing-press or otherwise. It is especially useful where the 
dies are "undercut" — that is, larger part-way down than 
they are at the top ; such are used for producing forms like 
the tea-pots, sugar-bowls, etc., often seen upon our breakfast- 
tables. In such cases the die must of course be split into such 
a number of parts as to enable it to open and the work to be 
removed from it. It is evident, however, that such a water- 
punch can enter it and be withdrawn without the difficulties 
incident to a solid punch. In some cases metal can thus be 
forced out into ornamental figures sunk in the surface of the 
die in a way not easy otherwise to attain. 

I have never heard of air or other gases being used in 



1 66 PRESS-WORKING OF METALS. 

this same way for metallic work, but such a pneumatic punch, 
entering a separable iron die, is the tool used every day by 
glass-blowers throughout the world. Another instance of 
similar work, minus the lower die, is seen in the industry of 
blowing soap-bubbles. 

Presses Suitable. 

For the various forming and embossing processes described 
in this chapter almost any type of press may or may not be 
suitable, according to circumstances. The type least likely 
to meet all conditions is, perhaps, a drop-press, which usually 
has the peculiarity of a faster moving and more loosely fitting 
ram than have other presses. These machines, however, are 
especially adapted to some kinds of embossing-work, and are 
sometimes used for forming, particularly in producing shallow 
pans, plates, trays, etc., in tin-plate and sheet-iron. In re- 
cent years they have been, for these latter functions, super- 
seded to a considerable extent by drawing-presses. For 
heavy embossing, a short-stroke toggle press, similar to those 
used for coining, is sometimes a very effective tool. 



CURLING AND SEAMING PROCESSES, 1 67 



CHAPTER VIII. 

CURLING AND SEAMING PROCESSES. 

Curling or Wiring. 

SOMEWHAT analogous to forming processes, but involving a 
new principle not yet herein touched upon, is the operation of 
" curling" or " wiring," with its various modifications. This 
consists of bending the end of each element of a cylinder, or 
truncated cone, or analogous hollow curvilinear-contoured ob- 
ject, with sheet-metal walls, either outward or inward into an 
approximate circle lying in an axial plane of the object itself. 
With outward curling the axial section of the object may there- 
fore resemble a short column surmounted by a torus, as in 
Fig. 288. The two words quoted as names for this process 
are used synonymously, although it would be more correct to 
confine the term "curling" to the operation of putting a 
curled edge upon the top of a pan, cup, or other vessel without 
any wire inside of it, this empty curling being often spoken of 
as " imitation wiring." Real wiring is the same process when 
done around a ring of wire, which, of course, stiffens the ves- 
sel very much more than does the bastard process before men- 
tioned. The latter, however, is cheaper and easier to per- 
form, and often answers a sufficiently good purpose. 

Outward Curling. 

In Fig. 285 is shown, in vertical axial section, a pair of out- 
side-wiring dies for cylindrical work, such as tin cups, dinner- 
pails, etc. This process, it should be mentioned, is usually 
confined to thin metals like tin-plate, sheet-iron, and some- 



i68 



PRESS-WORKING OF METALS. 



times brass and copper, all of which are usually less than g 1 ^ 
inch thick. In such tools the lower die L serves mostly as a 
receptacle for the work, while the upper die U does the actual 




Fig. 286. 



Fig. 285. Fig. 287. Fig. 288. 

curling. Were the dies in question for curling only, the 
loose ring a (which is driven to the upward position shown by 
suitable springs and limited therein by proper stops) might be 
omitted, the top of the die being solid, as in Fig. 289. As it 
is, this ring is used to support a ring of wire (usually bent 
around without joining), shown in Fig. 286. This is laid 
loosely around the top of the uncurled work, Fig. 287, and 
creeps down as the ring a descends by the action of U. The 
upward projecting wall at the top of the ring is to confine the 
wire loosely against its tendency to expand, perhaps irregu- 
larly, to such a degree that the down-curling edge of the sheet- 
metal would not be able to embrace it. This wall is tapered 
out larger at the top to allow the wire ring to enter more 
easily, and also to enable the curling edge to more surely pene- 
trate between it and the wire. At b is shown an adjustable 
bottom upon which the work rests, and which is regulated by 
the screw c or its equivalent. This construction enables the 
same die to be used for various heights of work. In cases 
where but one height is required this bottom is made in a solid 



CURLING AND SEAMING PROCESSES. 



169 



piece with the rest of the die, as in Fig. 289. In Fig. 288 is 
shown the finished work, as curled without containing the wire 
ring, such dies being available for making it either with or 
without the same. 

In Fig. 289 is shown a pair of curling dies for outside curl- 
ing upon the large end of conical or tapered work, such as is 




Fig. 289. Fig. 290. Fig. 291. 

shown uncurled in Fig. 290 and curled in Fig. 291. It is 
suitable for dish-pans, milk-pans, sauce-pans, buckets and 
such like work. Should it be desired to put in a real wire, 
the top of the die L is supplied with a " floating" ring, as at 
a, Fig. 285. This ring is, in some cases, made to contract or 
expand, to suit the changing diameters of conical work, in a 
manner similar to that of the sectional curling-rings to be de- 
scribed. 

In the tapered work we are considering it is evident that the 
curling, as it successively passes through the different stages 
shown in Figs. 318 to 321, inclusive, must grow smaller in its 
general diameter as it creeps down the cone to smaller and 
smaller diameters of the tapered work. It is therefore neces- 
sary that the curling-ring d should be detached from the re- 
mainder of the upper die, so that it can gradually decrease its 
diameter as it goes s downward in doing its work. That it may 
thus become a contracting ring it is made in a number of sec- 



170 PRESS-WORKING OF METALS. 

tions, usually being sawed apart radially into perhaps six or 
eight pieces. These are, of course, properly supported in the 
main body of U, and are supplied with springs to drive them 
outward as they ascend, so that they will be ready for the 
next piece of work. It is found in practice that such rings 
are sufficiently elastic to approximate nearly enough to a true 
circle as they are forced into the lower die, and that the slits, 
if narrow enough, do not injuriously mark the work. The 
work shown in Fig. 291 fairly represents the " body" of an 
ordinary sheet-iron bucket. These bodies are usually made 
up of one or two, or more, sections, seamed together in lines 
forming elements of the cone. 

In Fig. 292 is shown a pair of dies which are the exact reverse 
of those just described. They are for curling the small end of 
conical work, as shown in uncurled and curled conditions in 
Figs. 293 and 294, respectively. In general, it is found bet- 
ter to confine the work outside for outside curling, and it is 
therefore placed within the lower die, as a receptacle, in the 
two former cases above mentioned. In this case, however, 
it is evident that the work could not be gotten into and out of 
such a die unless it opened in halves, but experience has 
proved that work of the kind here shown (which, by the way, 
fairly represents coffee-pot bodies and such like articles) can 
be successfully curled after being slipped over the hornlike 
lower die pictured in Fig. 292, which seems to brace the body 
against "buckling" better than with straight work, etc. This 
and other dies of the same bulky character are often made hollow 
merely to save metal and make them lighter to handle. They 
could, obviously, however, just as well be solid, as far as their 
functions are concerned. The curling-ring d has in this case 
an expanding rather than a contracting action, and is forced 
inward by springs, instead of outward, as in Fig. 289. It of 
course expands automatically as it is driven down upon the 
work. 



CURLING AND SEAMING PROCESSES. 



171 



Inward Curling. 
In Fig. 295 is shown a pair of dies for the inward curling of 
a plain cylindrical body, Fig. 296, into the condition shown 




Fig. 294. 



a 



Fig. 295. 



Fig. 296. 



Fig. 297. 



in Fig. 297. Sometimes this process is practicable at both 
ends of the work at once by the use of double curling- dies. 
In this way it is well adapted for certain forms of napkin- 
rings, etc. Such dies can, of course, be arranged for real 
wiring if desired. 

In Fig. 298 is shown a pair of dies for the inward curling of 
the large end of conical work, as shown in Figs. 299 and 300, 



172 



PRESS-WORKING OF METALS. 



respectively. In this case the curling-ring is, of course, a con- 
tracting one. 

In Fig. 301 is shown a pair of dies for the inward curling of 




Fig. 301. 



Fig. 302. Fig. 303. 

the small end of conical work, as shown in Figs. 302 and 303, 
respectively. In this case the curling-ring d expands. 



Assembling by Curling. 

In Figs. 304 to 312, and also in Figs. 314 and 315, are 
shown specimens of what might be called the curiosities of 
curling. They are combination processes, where two or more 
pieces previously made of the proper shape are assembled and 



CURLING AND SEAMING PROCESSES. 



1 73 



fastened together, as well as given a suitable finish by various 
operations of curling, etc. 

In Fig. 304 are shown the uncurled body, bottom, and base 
ring of a patent coal-scuttle, one side only being given, and 
that in "slice-section." In Fig. 305 the same are shown, in 
complete section, after being curled at one operation, the dies 
at the same stroke curling the top rim e, the triple joint /, 




Fig. 308. Fig. 309. Fig. 311. Fig. 312. 

and the bottom rim g. Dies for such work are, of course, 
very difficult to make, especially as the top of the vessel does 
not lie in a normal plane, nor in a plane at all, being of the 
double spiral shape shown. It is, moreover, necessary to use 
self-acting outside clamps to clamp the body securely to the 
horn, and also to embody certain vertical motions of the horn 
itself, and of a clamping device to hold the bottom and base 
ring in place. 



J 74 



PRESS-WORKING OF METALS. 



In Figs. 306 and 307 are shown two similar stages of the 
operation of curling the top of a bucket and putting a bottom 
thereon, the latter, however, not being a curling operation, 
but rather a peculiar style of forming, where an upwardly pro- 
jecting bead in the bottom, k, is forced to bulge and bend 
over outwardly by the pressure brought upon it at the same 
time that the top curling is being done. 

In Figs. 308 and 309 are shown similar stages of the opera- 
tion of putting the bottom in a bucket by a different method, 
consisting of double-curling them together at g, while the top 
curl is being made at e. In this case a depression, h, has been 
made in the body in some kind of a roller forming- machine. 

In Figs. 311 and 312 are shown similar successive stages 
in the operations of putting together a sheet-metal cuspidor. 
The curling at e, however, has in this case been done in a 
lathe, because the taper of the cone (see, also, Fig. 310, as 
before curling) was too great for curling-dies to work properly. 




^ F 

M i l ' " 111 





Fig. 313. Fig. 314. Fig. 315. 

The operations at / and h consist of a sort of a combined 
curling and smashing, somewhat similar to that shown in Fig. 
307. At g and i the action is true curling, done in an inward 
direction. 

In Fig. 313 is shown a pair of dies for putting together by 
the process of inside curling a body and a bottom, as shown in its 



CURLING AND SEAMING PROCESSES. 



175 



successive stages in Figs. 3 14 and 315, respectively. The func- 
tion of the spring-driven-up plate a in the lower die is to sup- 
port the bottom when first laid upon it, but it of course de- 
scends therewith as the curling proceeds. 



Principles of Curling. 

In analyzing the principles of the curling process we will 
find that, with the dies under consideration, it cannot be 
practiced upon the edge of a flat sheet of metal, and that said 
metal must not lie in a plane, but in the surface of a cylinder, 
or approximately so. It is, therefore, not practicable, with 
ordinary curling-dies, to curl or wire rectangular utensils or 
other articles having a prismatic or pyramidal rather than 
a cylindrical or conical form. It is true that a curling action 
might take place at the angles of such pyramids or prisms if 
they were somewhat rounded off to a curved contour, but at 
the sides, where the edge followed straight lines, it would 
simply be bent, as at the top of M, Fig. 316, instead of 
being truly curled. 

In Figs. 316 to 321 are shown at U, in partial vertical 




axial section, one side of a broken-away curling-ring, and at 
M, in Figs. 318 to 321, similar sections of a piece of plain 
cylindrical work near its upper end, these latter pictures show- 



176 



PRESS-WORKING OF METALS. 



ing various successive stages as the die U descends in the 
operation of true curling. 

In Fig. 316 is shown the bending action before referred to, 
where the edge of the work lies in a straight line. Or, for the 




Fig. 320. Fig. 321. 

sake of illustration, let us suppose that M is a little bar of 
metal, standing on end, and say ^ T inch thick by \ inch wide, 
shown in edge view. It is evident that when this straight 
vertical bar is struck by the inclined surface of U, at the point 
a and below, it will be bent outward, but with a long bend, 
as shown, instead of a short one, as in Fig. 318. This is by 
reason of the ordinary principles of leverage, which cause a 
bar to bend as far as possible from the end where the force is 
applied so as to obtain more leverage for such bending, its 
starting-point being determined in this case by the outside 
resistance at b, which is supposed to be the confining part of 
the lower die. If the operation is carried a little further, the 
top end of the bar reaches a point in the die at c, where it 
stands at right angles to the surface of the same and can be 
coaxed no further sidewise, but only buckled. The result is a 
general smash, or perhaps it is carried down in some irregular 
and undesired form. If, however, when it first starts to bend 
outward it could be confined at the point d on its surface, and 
after the extreme end is bent into a short curve it could be 
again confined at e, and still later at '/, it is evident that it 
would assume the proper shape and approximately follow the 



CURLING AND SEAMING PROCESSES. 177 

semicircular curvature of the die at a c. To illustrate more 
plainly : Supposing that we have a vessel composed of a num- 
ber of the small bars, M, arranged in a circle like the staves 
of a barrel, and supposing that we have a hoop at d which will 
confine them all until a bend is started at each of their ends, 
and that then it will expand and another hoop at e will hold 
them until they are again bent, when this hoop in its turn 
expands — and so on. Such an arrangement would evidently 
develop a curling operation, and the action described is what 
really takes place, the sheet of metal itself being at the same 
time its own staves and its own hoops. To prove that a square 
can could not be properly curled along its flat sides it is only 
necessary to imagine a square barrel, in which, obviously, the 
hoops would have but an infinitely small resistance to the 
initial expansion of the staves, except at the corners and in 
their near vicinity. 

With inside curling the holding-in action at d, e, f, etc., is 
due to the compressive instead of the tensile resistance of the 
metal in a circumferential direction, as before. Then, by anal- 
ogy, we have the arch instead of the hoop principle, and our 
little staves become the arch-stones. 

When the top of a piece of metal has once been set into 
a curve of small radius at the extreme edge, and when the 
forming of the incipient curl thus commenced is gradually 
continued, as in Figs. 319, 320, etc., there is no action tend- 
ing to straighten it out again, except (in the case of outside 
curling) the resistance of the edge of the metal to compression 
as it travels inward from g to k, Fig. 321. This resistance is 
not, however, as has been proven in practice, sufficient to 
spoil the curl, which consequently progresses inward until it 
strikes the main body of the metal; or, indeed, if the process 
be continued long enough, until it goes on around in a spiral 
form, as shown in Fig. 322. With internal curling the cir- 
cumferential stresses in the edge of the metal as it travels from 



178 



PRESS-WORKING OF METALS. 



g to h are of course tensile instead of compressive, but. again, 
are not sufficient to balk the curling propensities existing. 

It is evident that as the edge of the metal travels outward 
from a to c in external curling it must be stretched or made 
longer circumferentially. This, in some cases, is sufficient to 
crack it in a radial direction at numerous points around it. 
To guard against this the diameter of the curl must not be too 
large in proportion to the diameter of the vessel operated 
upon. Its behavior in this respect depends also upon the 
thickness and toughness of the metal. If, again, the curl 





Fig. 322. Fig. 323. Fig. 324. 

/tself is too large in relation to the metal's thickness, the edge 
does not go in properly from g to h, according to a tendency 
that was predicted for it in the last paragraph. Sometimes, 
indeed, with the large curling used with real wire, it is neces- 
sary to roll the edge down afterward in some kind of a "bur- 
ring" machine. Especially is this apt to be the case with 
external curling upon work with considerable taper, like dish- 
pans. The large diameter of the pan, the largeness of the 
wire which is usually put in, the greater distance from g to h 
on account of the taper, and the proportionate thinness of the 
metal, all serve to present bad conditions for true curling. 

With internal curling there is less trouble in regard to the 
points above mentioned, but as the edge of the metal is first 
compressed and becomes smaller in traveling from a to c, it 



CURLING AND SEAMING PROCESSES. 1 79 

must be expanded and stretched in completing its journey 
from g to h, this being exactly the converse of the other case. 
If tough enough it will go all right; if not, otherwise. 

In practical work it is found that with ordinary tin-plate 
and sheet-iron a curl of from -£% to T 3 ^- inch in diameter can be 
obtained, according to various conditions above indicated. 
For larger curls to be successfully made, much thicker metal 
might be required. 

Straight Curling. 

An exception to the working of the general principle above 
mentioned, which prevents the curling of an edge of sheet- 
metal standing up in a straight line, may be arranged for by 
a peculiar form of die, where the wall of metal at fb, Fig. 
316, is held from bending away from the upper die's vertical 
working surface by a special supporting plate forming part of 
the lower die, which confines and supports the metal, but 
which slides down out of the way, as the upper die descends. 
This construction is not very common, but has sometimes 
been used for curling the straight sides of a square dinner- 
pail, and similar work. 

Another exception to our somewhat elastic rule is found in 
the case of very shallow work, like a", Fig. 284, for instance, 
where the rigidity of the flat bottom, or web, of the article, 
together with the stiffness of the low standing-up edge, serve 
to hold the metal at the beginning of the curl nearly to its 
original position — at any rate for inward curling. 

Horning or Side-seaming. 

Somewhat germane to the subject of curling and wiring, 
inasmuch as it is used in preparing utensil bodies for that 
process, is the operation of horning or side-seaming. This 
also is an assembling process, where two or more pieces are 
fastened together by press work, and is analogous to some of 



i8o 



PRESS-WORKING OF METALS. 



the putting-together operations described a few paragraphs 
back. 

In Fig. 323 is shown a front view of a round " horn," L, 
which is, of course, in reality a lower die, and of an upper 
die, or so-called "force," U. These, as shown, are adapted 
for closing down a side seam upon a cylindrical or conical 
" body " with an outside projection, as in Fig. 327. At G is a 
row of disappearing gauge-pins, against which one edge of the 
metal is placed. These are pushed down by the other over- 
lapping edge as it is depressed by the force U, and rise again 
by springs placed beneath them.. 

In Fig. 324 are shown a horn and force adapted for square 
work rather than round. In this case the horn is grooved and 
the face of the force is flat, thus adapting it for an internally 




Fig. 325. 



Fig. 326. 



Fig. 327. 




Fig. 328. Fig. 329. Fig. 330. 

projecting seam like that in Fig. 326. Either form of seam 
can, of course, be made in either round or square work, 
these horns being shown as random specimens merely, repre- 
senting two common forms of contour and both kinds of 
seams. In some cases a seam is made at one corner of a 
rectangular horn, instead of at the side. 

In Figs. 325 and 326 are shown the successive stages of 
an ordinary " lock-seam," the first showing it loosely hooked 
together, the hooks having been previously formed separately; 
and the second showing it after being struck and smashed 



CURLING AND SEAMING PROCESSES. l8l 

down solidly together in the press. In Fig. 327 the same 
thing is shown, but with the seam projecting outwardly, as 
before mentioned. 

The articles requiring these lock-seams are very numerous. 
A few among them are spice- and mustard-boxes, some fruit- 
and meat-cans, buscuit-boxes, petroleum-cans, powder- 
-kegs," stove-bodies, etc., together with a variety of pans, 
pails, and pots. The class represented by the last three men- 
tioned, when not drawn from a single blank, is known as 
" pieced ware." A vessel like a large bucket or a dish-pan is 
sometimes made with several side seams at various points 
around its body. The bottoms of these utensils are usually 
fastened on by " double-seaming " in a special rotary machine. 
All the seams are, in the case of tin-plate, reinforced with 
solder, and in the case of "black-iron," by tinning or enamel- 
ing the article all over. In boxes and canisters for holding 
dry substances the seams are usually left untouched, as they 
come from the machine. 

In Figs. 328, 329, and 330 are shown, more as a curiosity 
than anything else, three successive stages of a peculiar 
patented seam which I once designed a special press for, the 
ram being supplied with three different dies, each putting 
itself in position, successively, during three quick blows which 
the press gave before stopping. The horn also was provided 
with an automatically-changing lower die. The work was 
placed in the machine without hooks, as in Fig. 328, the 
three successive blows putting it first into the shape 329, then 
into 330, and finally smashing it so that it looked pretty much 
the same as Fig. 326. This seam was a success mechanically, 
especially for thin sheets, although somewhat wasteful of 
metal. For some reason unknown to me the owners have 
never put it upon the market. 

There are numerous other forms of special seams which do 
not appear to have come into practical use, and there are also 



1 82 PRESS-WORKING OF METALS. 

some patented machines for making automatically the ordinary 
locked seam first described. These, however, it will hardly 
be worth while to describe here. 

Speeds and Pressures. 

The ram speed in running curling dies is immaterial, there 
being no limitations in this respect as presses are ordinarily 
operated. 

The speeds used in seaming work are also indefinite, 
although, with a given size of press, a quick hammer-like 
blow would be likely to prove most effective. 

The pressure needed for curling is usually small, it being 
quite possible to use a foot press upon tin-plate worked up to, 
say, about 12 inches in diameter. In the lack of accurate 
data a safe pressure allowance would probably be from 100 to 
200 pounds per lineal inch of curl, or circumference of utensil. 
This is counting the metal not over -$\" thick. In general, the 
pressure would most likely have to be increased approxi- 
mately as the square of the thickness. 

The pressure required for seaming is much greater, and 
can hardly be too much, if kept well within the crushing 
strength of the metal. Again we have no accurate records of 
what is needed for each particular set of conditions; but, 
roughly speaking, an allowance should be made of from 2000 
to 4000 pounds for each inch of seam length — that is with 
ordinary tin-plate and sheet-iron. 

Suitable Presses. 

The kind of press used for curling is not of much conse- 
quence except that it must have height enough for the depth 
of the dies, which is usually much greater than for work of 
other kinds, plus the depth of the work itself, so that it may 
be inserted between them and then dropped into or on to the 
lower die. This is assuming the lower die to be fastened to 



CURLING AND SEAMING PROCESSES. 183 

the piess-bed in the ordinary way, and would, of course, in- 
volve an extra long stroke to the ram. In practice, however, 
except for very shallow work, the lower die is generally mounted 
upon a sliding or swinging table, which is brought forward 
each time the work is to be removed and replaced. It is then 
pushed backward (by hand, usually) under the upper die, 
which need have but an ordinary stroke of from 1 to 2 inches, 
•according to the character of the particular dies in question. 
In this case the height from the bed, or rather the bolster, to 
the ram, with ram up, need be but the "shut-height" of the 
dies plus the stroke, as usual. Obviously, however, such dies 
are apt to average higher than do cutting dies, etc. 

The presses used for horning are usually made on purpose 
for the work, with the projecting bed omitted from the frame, 
■and in lieu thereof special means for inserting or otherwise 
fastening on horns of various sizes and shapes. For certain 
small work ordinary presses can be used, with horns mounted 
upon properly adapted bolsters. 



1 84 PRESS-WORKING OF METALS. 



CHAPTER IX. 
DRAWING PROCESSES. 

Drawing, Historically. 

The drawing process for sheet-metals, by which deep 
cylindrical, conical, and other cup-shaped articles are made 
seamless from a flat sheet, is very different from the ordinary 
forming process used for shallow articles of like general na- 
ture; or, to speak more accurately, it is an amplification of 
the same, embodying certain new and entirely different prin- 
ciples. It is in its nature as interesting as it is unique. It 
is, moreover, a comparatively new process, probably dating 
back not more than 50 or 60 years. As near as I can learn it 
was first used in America by Mr. Grosjean of New York, who 
informs me that he thinks it was practiced in France over 
half a century ago. I am informed by Mr. Neidringhaus of 
St. Louis that the Prussian system of metal-drawing, as it is 
called, was invented at Saarlouis, Rhenish Prussia, by the 
Strouvelle Brothers. It probably was not practiced on a 
large commercial scale in this country much earlier than 1866, 
and the first presses were made here by a Mr. Marchand, who 
had been employed by Mr. Grosjean and his associates. 

This process is sometimes called " stamping," which term, 
however, is a misnomer, being improperly used to designate 
something which is the successor of the old stamping process, 
but entirely different from it. The latter was practiced for 
many years in the production of various seamless utensils, 
such as pans, bowls, plates, cups, etc., which were gradually 



DRA WING PROCESSES. 



185 



coaxed down into shape, so to speak, by frequently repeated 
blows in a drop-press. 



Drawing Defined. 

Sheet-metal drawing, proper, consists in so confining a 
certain outer zone of a blank (which is to be drawn into a cup- 
like shape) between two rigid flat surfaces that the metal 
cannot wrinkle when pulled radially inward, which it attempts 
to do on account of the constantly decreasing circumference 
of its edge. In Fig. 331 is shown, in vertical axial section, 
a pair of combination push-through drawing-dies, of the sort 






Fig. 332. 



Fig. 334. 




o 



Fig. 331. Fig. 333. Fig. 335. 

used for any plain cylindrical articles of medium depth, such 
as blacking-boxes, can-covers, clock-cases, etc. They consist 
of a lower die, L, an upper die, U, and a drawing-punch, P. 
They are shown with cutting-edges, c, c' , for which reason 
they are termed " combination-dies " — as a sheet laid between 
them when U descends is first cut into a blank, as shown in 
two views in Fig. 332. They could, however, just as well be 
used for blanks already cut, the edge c' being in such case 
somewhat rounded off to facilitate easy entrance of the blank, 
and remaining to serve the purpose of a gauge merely. 
Where blanks rather than whole sheets are used, this gauge- 
ring may be omitted and gauge-pins substituted therefor, as 
in Fig. 340, at G G. In some kinds of work no gauges are 
used except the fingers of the operator, the top surface of the 



1 86 PRESS-WORKING OF METALS. 

die being made of exactly the same size as the blank, to 
facilitate adjusting in this way. 

Mechanics of Drawing. 

The operation of these tools is as follows; The die £7 de- 
scends until the blank is firmly clamped between it and the 
die L, at which time £7 stops, the ram of the press being pro- 
vided with a proper " dwell " until the punch P has had time 
to descend, forming the work gradually to shape, as shown by 
its successive stages in Figs. 333, 334, and 335. The punch 
then ascends, the work being prevented from rising by the 
sharp, hard stripping-edge s. The slight expansion of the 
P 




Fig. 337. 

Fig. 336. Fig. 338. Fig. 339. 

top edge of the work by its own elasticity is usually suffi- 
cient to prevent its pulling up through the die again. In 
some cases, however, there is a tendency to do so, which can 
be prevented by three or more spring-pawls inserted in the 
die at a point below s. 

In all work of this kind it is important to vent the punch 
by an air-hole of ample size, somewhat as shown in Fig. 343, 
as otherwise there is a tendency for the work to be drawn 
upward by suction. This vent has been omitted from the 
other engravings. 

It is evident that if the die U remains stationary during 
the drawing of the work the thickness of the flange thereof 
— that is to say, the flat part from the edge inward, which 
would be the rim of the inverted " straw hat," so to speak, 
represented by Fig. 333 — must remain of the same thickness 



DRA WING PROCESSES. 



as the original blank. Consequently the sides of the finished 
cup, Fig. 335, as well as its bottom, will remain of uniform 
thickness — that is, if there happens to be sufficient room 
between the sides of punch and die, so that the metal is not 
squeezed thinner. It may be said that the die U might be 
easily forced upward by the attempted thickening of the 
metal, the press springing open to allow for the same. This 
is true, but in practice the fact is that the thickness is 
changed but little. We have, therefore, in this process an 
interesting action taking place in the flange, viz., the crowd- 
ing together— in blacksmith's parlance the "upsetting" — of 
the metal in a circumferential direction, while a pulling apart 
or stretching action is going on in a radial direction, and that 
to an amount, as experience proves, just about sufficient to 
balance the other. 

This action is very prettily shown by a graphic method. 
Four small dots arranged in a square are marked upon the 
blank, as in Fig. 332, and this square will be seen to have 




Fig. 341. 



Fig. 340. Fig. 342. 

elongated itself radially and shortened itself circumferentially 
into the form of a diamond during different stages of the 
work, becoming a very elongated one at the last. The same 
action is shown in Figs. 349 and 350, which were photo- 
graphed from an actual piece of drawn-work about 5 inches 
in diameter by something over 2 inches deep, the blank for 
which was made of "decorated tin," upon which were ruled 
cross-lines, as shown. The new relations of these lines to 



1 88 PRESS-WORKING OF METALS. 

each other upon the sides of the cylindrical cup tell the 
story far better than mere words can do. 

Flow of Metals. 

There is evidently here an interesting instance of the cold 
flow of metals, the molecules thereof being obliged to move 
freely among themselves and arrange themselves in new posi- 
tions. Such flow takes place, as experience proves, without 
weakening the metal, it merely growing somewhat harder, in 
the same way as it would in any hammering or rolling opera- 
tions. This subject has been previously treated by the 
writer in a lecture delivered by him before the Franklin Insti- 
tute, entitled "Flow of Metals in the Drawing Process," 
which was published in the Journal of the Institute for No- 
vember, 1886. The following paragraphs are quoted there- 
from : 

" Common instances of elastic flow may be found in the 
wonderful stretching of a piece of india-rubber to perhaps ten 
times its normal length and its indignant return to exactly its 
original form, or in the bending or twisting of any wooden or 
metallic springs, etc. 

" Instances of non-elastic flow are observed most fre- 
quently, perhaps, in connection with semi-solids, such as the 
clay upon the potter's wheel, the dough in the hands of the 
housewife, or the putty under the glazier's knife. In the ap- 
parently rigid solids such action is not popularly conceivable, 
but a little observation will show that the cold-forging of a 
piece of iron, or, indeed, any bending or other permanent dis- 
tortion of any piece of metal, could not occur without this flow- 
ing of its molecules among themselves. Such flowing is shown 
on the grandest scale known to our present experience (what- 
ever may have happened in the mighty workshops of geologi- 
cal science) in the glaciers of the Alps, where great masses o£ 
solid ice flow slowly down their confining channels, changing 



DRAWING PROCESSES. 1 89 

their shape of cross-section as needs be, without being crushed 
or suffering any disintegration of their substance. This has 
been well described by Professor Tyndall, and it is, if I re- 
member rightly, the same distinguished prowler about Na- 
ture's portals who tried the very interesting experiment 
regarding the flow of foreign objects through solid pitch 
without leaving any holes in it. I could not find the de- 
scription of this experiment the other day in any books that I 
had at hand, but I believe it was as follows: A number of 
stones were placed upon the top of, and a number of corks 
underneath, a mass of pitch several inches thick, and aban- 
doned to their fate. After several months of silent disap- 
pearance the corks arrived at the top and the stones at the 
bottom of the pitch, having floated and sunk respectively to 
their natural destinations. 

" In looking for the flow of solids in the metallic arts it 
will be well to omit all hot processes as dealing with semi- 
fluids; but familiar examples of cold flow may be seen in 
wire-drawing, tube-drawing, cold-rolling, and -hammering, 
lead-pipe making, sheet-metal spinning, etc. 

"The first two mentioned are obviously analogous, about 
the only difference being that the tube is hollow, usually 
with a mandrel inside of it, while the wire is solid. Very 
similar to these operations, as respects the direction of flow 
of the particles of metal, is the reducing of a rod in grooved 
rolls, the chief difference being that the metal is coaxed 
along by friction, so to speak, instead of being pulled by its 
finished end. In hammering a bar the tensile stresses are 
entirely omitted and the action is wholly compressive, in a 
lateral direction, of course. 

" In lead-pipe making we have also an entirely com- 
pressive action, but one very different from that in the last- 
named process. Here the lead is squirted out, as it were, 
much after the manner of a syringe, or a sausage-stuffer, or 



190 



PRESS-WORKING OF METALS. 



one of those curious but really excellent squirting brick- 
machines. . . ." 

Conical Drawing. 

In Fig. 336 is shown a pair of conical drawing-dies, the 
blank and successive stages of the work being shown re- 
spectively in Figs. 337, 338, and 339. Perspective views of 
finished work from dies of this sort are shown in Figs. 354 to 
359. Large-sized dies of this kind are usually made of cast- 




Fig. 344. 



rzzzi 

Fig. 343. Fig. 345. 

iron, without cutting-edges, the gauging being done by hand,., 
as before mentioned. Where there is considerable taper to 
the work, it is removed by the hand of the operator grasping 
it inside and lifting it merely by friction as he pulls it upward 
and sidewise. The presses for doing this are run very slowly 
(sometimes not over 8 or 10 strokes per minute) with contin- 
uous strokes, not stopping by the clutch with the ram in up 
position, as is usual with smaller presses. This is, of course, 
somewhat dangerous, as a man's arms would be crushed to a 
jelly were he to fail in keeping time with the motions of the 
press, even perhaps by the fraction of a second. It is rarely, 
however, that accidents of this sort happen. 

In Fig. 340 is shown a somewhat similar pair of dies, ex- 



DRA WING PROCESSES. 



I 9 I 



cept that they are nearer hemispherical than conical, and are 
provided with a knockout, K, which rises at the proper time 
by a spring, or automatically by the motion of the press. 



Fig. 346. 



XZ "XT" 



Fig. 347 



Fig. 348. 




Fig. 351. 




Fig. 352. 



Fig. 353. 



Fig. 354. 



Such knockouts are of course used in dies of either of the 
forms described, and they are sometimes omitted in the bowl- 
shaped work (see Fig. 342) made in the dies now under dis- 



I9 2 PRESS-WORKING OF METALS. 

cussion. The necessity of such a knockout is of course de- 
pendent upon whether the work is steep enough at any place 
to cause it to stick fast and thus prevent a free delivery. In 
Figs. 358 and 359 are shown perspective views of a bowl and 
cup made in dies of this sort. 

Depth of Drawing. 

The depth of work attainable by the drawing process de- 
pends upon various conditions, among which are the kind and 
toughness of metal, the thickness thereof in proportion to the 
diameter, the smoothness of the dies, etc. I have known 
small articles to be drawn at one operation from a good qual- 
ity of " one-cross" tin-plate, which is about ¥ 1 ¥ inch thick, to 
a depth equal to one half their diameter. Occasionally this 
proportion has reached two thirds, as, for instance, a 3 -inch 
round box 2 inches deep, etc. ; but such would be an extreme 
case. Brass, german-silver, and copper can usually be drawn 
somwhat deeper, while zinc, on account of its tensile weak- 
ness, has limitations of shallowness which are sometimes very 
provoking. Silver and gold are well adapted for deep work, 
but I cannot learn of the latter metal having been tried for 
anything as large as a churn. Recent experiments in the 
drawing of aluminum show it to be well adapted to the proc- 
ess. It is especially convenient on account of working with- 
out so frequent annealing as is necessary with brass, iron and 
steel, etc. Its tensile strength, however, being somewhat less 
than brass, prevents, in some cases, so great a depth being ob- 
tained at one operation. In various experiments conducted 
by the writer in drawing cartridge-shells of this metal it 
showed itself most excellently adapted to the purpose, as it is 
also to all sorts of cooking-utensils, which are drawn without 
difficulty in the ordinary forms. These, on account of their 
healthfulness, lightness, and beauty, are, I think, destined to 
undergo an enormous development. 



DRA WING PROCESSES. I93 

It may be asked why some of the weaker metals cannot 
be drawn as deep as stronger ones, considering that their com- 
pressive resistance to upsetting is probably somewhere nearly 
in proportion to their tensile strength. An explanation may 
perhaps be found in the flange-friction, between the die-hold- 
ing surfaces, remaining nearer a constant than do some of the 
other conditions. There are, however, a good many things 
in the physical structure of the various metals regarding which 
we must, for the present at least, retain an agnostic attitude. 

To quote again from the lecture before mentioned, and 
referring to Fig. 331: 

"A little study of the work which is being done in a die 
like this will show why a limit of depth is soon reached. The 
actual work done consists, firstly, in overcoming molecular 
friction, or causing to flow among themselves the particles of 
metal in the flange before and while it turns the corner d; and 
secondly, in overcoming the friction between the upper and 
lower sides of the metal and the surfaces of the dies. If we 
imagine the part of the work which has become cylindrical to 
be a series of little ropes (forming the elements of the cylinder) 
which are attached to the punch by running across under the 
bottom of it and thence up its sides to the corner d, we will 
see that all the resistance offered in the flange is being over- 
come by the punch pulling these ropes downward over the 
corner d, it acting as a stationary pulley-block, as it were. 
Hence if the united tensile strength of all these little ropes is 
great enough to overcome the resistance at its maximum, 
which is soon after the metal begins to flow, when the flange 
is at its widest, perfect work will be the result. If, however, 
there are not enough ropes to do this work, which is the case 
when the diameter at s is too small, the flange will not start 
to move, but the punch will simply go down and tear the 
bottom out of the work. Thus if we try for too great a depth 
relatively to the proposed diameter the work will be spoiled, 



194 PRESS-WORKING OF METALS. 

because this means a wide flange, to furnish more metal — and, 
consequently, more resistance. 

" It is evident that the little ropes spoken of will render 
more easily about a large corner than a small one, and that 
therefore a better result may be obtained by increasing the 
radius of the "drawing-corner" d. If, however, this is car- 
ried too far, a considerable part of the flat holding-surface of 
the lower die is lost, and a new evil arises, known as body- 
wrinkles, which will be explained further on. Practically, for 
working tin-plate, the radius of the corner d is made from ■§- 
to \ inch. The curvature of the corner r upon the punch also 
affects the result. If it is made perfectly sharp, it tends to cut 
the metal which is pulled around it, and practically ought not 
to be less than j\ inch radius. It is often much larger than 
this to suit shape of work desired, but if made very large it 
causes the trouble of body-wrinkles before referred to, on 
account of there being a certain zone of the blank which is 
unconfined by the flat holding-surfaces." 

In conical work the difficulty in regard to getting enough 
tensile strength of metal to pull in the flange is often greater 
than in cylindrical, as the hypothetical little ropes spoken of 
in the above quotation are still fewer in number around the 
small circle whose perimeter is at b, Fig. 336, than they would 
be-in the larger one at t, with a cylindrical punch. In general, 
therefore, work with a diameter at the bottom small in pro- 
portion to the extreme diameter of the flange is difficult to 
draw. This is shown in Figs. 346, 347, and 348, where there 
is a great deal of work going on in the vicinity of the flange 
in comparison to the amount of strength around the point of 
the punch to do the pulling. 

Body-wrinkles. 

In conical work like Fig. 339, or with approximately 
spherical shapes like Fig. 342, the blank is evidently uncon- 



DRA WING PROCESSES. 1 95 

fined over a certain annular zone lying between the lower 
corner of the punch b and upper corner of the lower die d, 
represented in general by the distance b t, Fig. 336. As the 
inner portions of the flange enter this zone and pass inward 
over its surface they are obliged to become smaller in circum- 
ference. There are here no clamping die-surfaces to prevent 
wrinkles, which are therefore naturally formed and carried 
down into the conical portion of the work, as shown in Fig. 
351, which was photographed from an actual washbowl about 
10 inches in diameter, just as it left the dies. These are known 
as "body-wrinkles," in contradistinction to the "flange- 
wrinkles," which sometimes occur when the upper and lower 
dies are not set tightly enough together. The former are 
usually removed by roller-spinning in a special lathe. The)' 
are apt to occur in almost any of the utensils shown, except 
perhaps in work like the pie- plate, Fig. 354. This is so shal- 
low that they only barely begin to form, especially as the 
flange can be clamped very tightly in proportion to the depth, 
so that there is a tendency to pull out these incipient wrinkles 
by the actual stretching of the conical body of the work. There 
are other cases where wrinkles do not form objectionably on 
account of the work having very little taper, as in Fig. 357. 

In Figs. 352 and 353 are shown common forms of cake- 
pans, which illustrate body-wrinkles when systematized and 
intended purposely to remain. These are the easiest made of 
all forms of deep work, and do not require a holding-die at all, 
being made without trouble in a single-action press. 

Flange- wrinkles. 

The absence of wrinkles in the flat flange of metal between 
the dies, which represents what remains of the original blank, 
is obviously due to sufficient die-pressure being maintained 
throughout the operation. Conversely, their presence (always 
as a nuisance) is due to the upper die being insufficiently forced 



I96 PRESS-WORKING OF METALS. 

down, or to the press springing open afterward. If they once 
begin to form, it is almost impossible to smooth them out 
again. In straight work they are apt to show permanently in 
the walls of the article produced, while in conical or other 
tapering work they go down and aggravate the evil of body- 
wrinkles. 

In general, therefore, any "blank-holder" (as the upper 
die is often called) should be set down as firmly as the metal 
will stand without tearing. Furthermore, it should be set 
evenly, ascertaining the average of such a condition by 
repeated trials, as some irregularity in the thickness or hard- 
ness of the blank may prove misleading at first. All good 
drawing-presses are provided with some sort of a "tipping" 
'adjustment, either in the ram or bolster, by which the above- 
earned result may be obtained. 

Proportions of Work. 

Obviously, large diameter, in proportion to depth of draw, 
ensures less tendency to wrinkles and breakage, and is a con- 
dition requiring less power to make the metal flow. 

Thick blanks are less liable to breakage than are thin ones, 
for the same reasons, connected with friction in its proportion 
to cross-section, that are given further on in relation to mul- 
tiple drawing — and, too, because less " holding "-pressure is 
needed. 

There is with thick blanks also less tendency to wrinkle 
because of the reluctance of the stiffer metal to bend or buckle 
out of its original plane, in obedience to the circumferential 
upsetting action we have been considering. This stiffness is 
approximately as the square of the thickness, and hence we 
find that in drawing "clumsy" articles, so to speak, such as 
some forms of cartridge-cups, gong-bells, heavy boiler-heads, 
etc., we do not need any flange-pressure at all. In such 
case the process becomes really a forming one, notwith- 



DRAWING PROCESSES. 1 97 

standing the use of a double-action press and dies. The latter 
are referred to in Chapter VII ; and certain double-action 
crank-presses which are sometimes used for such dies are 
mentioned in Chapters II and III. 

From the analysis given it will be seen that, in general, 
the least difficult articles to draw, with a given metal, are 
those which are comparatively thick, flangeless, shallow, flat- 
bottomed, and cylindrical rather than conical or irregular. 

, Multiple Drawing. 

It has been seen that the resistance to be overcome in 
drawing is due to both surface-friction against the dies and 
to molecular friction, or resistance to flow. With such coni- 
cal articles as bowls, pans, etc., which do not require to be ab- 
solutely of uniform size, advantage is taken of this division of 
resistance by drawing two or more together — sometimes as 
many as four. In such a case the surface-friction is no 
greater for four than for one, as there are but two surfaces 
sliding against the dies. The molecular friction is, of course, 
four times as great as with one, but the sum of these frictions is 
obviously less in proportion to the tensile strength of the wall of 
metal surrounding the punch, which is as the number of thick- 
nesses involved. There is, therefore, a considerable gain in 
strength, and deeper work may be made than where one is 
drawn at a time. 

Formulating the above, with a view of showing the prin- 
ciple merely without introducing actual values, letting T = 
total tensile strength of wall of metal around punch, R = 
total resistance of flange against being pulled down into the 
formation of said wall, vS" = total surface-friction, M = molec- 
ular friction, and x = such amount of R as is due to the fric- 
tion of one surface, we have R = S -\- Af, and 5 = 2x, due 
to the two sliding surfaces. We will assume T = 4.x 
and M = 3^, as being a rough approximation of the truth — 



I98 PRESS-WORKING OF METALS, 

at any rate with some metals, some dimensions, and some ram- 
pressures. Hence, regarding the drawing of one blank at a 
time as Case 1, two blanks as Case 2, etc., we have in 

(Case 1) R = 2.x -J- $x = $x, and T = 4.x, which is < R, 
(Case 2) R = 7.x -{- 6x = Sx, and T = Sx, which = R, 
(Case 3) R = 2x -j- gx = 1 ix, and T = \2x, which is > R. 

It is obvious that if R exceeds T, as in Case 1, the blank 
cannot be drawn at all, but must be burst through by the de- 
scending punch. With Case 2 the results would be doubtful; 
but when T exceeds R by a small percentage, as in Case 3, 
only a few breakages will occur. With greater excess, such 
as would be attained with four blanks (and these other hypo- 
thetical conditions), there would be practically none at all. 
The safety limit, here occurring between one and three blanks, 
may of course happen at some other point when the various 
conditions are different. 

It is customary to remove the several thicknesses together 
from the press, sometimes spinning them in this condition, 
after which they more or less easily drop apart. Obviously 
this could not well be done with cylindrical articles, as the 
difference in diameter would be too apparent, and, moreover, 
they could not be easily separated. 

Condition of Dies, Etc. 

Referring again to the condition of the dies, it is very nec- 
essary, in order to avoid surface-friction, that they be made 
exceedingly smooth and that the flat surfaces should be truly 
parallel, thus giving a space of uniform thickness between 
them. It is better to polish the clamping-surfaces radially 
rather than to leave a "lathe polish" upon them — a quite 
perceptible difference in preventing the metal from cracking 
sometimes appearing under such conditions. 

Lubrication, which in certain cases is needed with various 
other kinds of dies referred to in this treatise, as mentioned 



DRAWING PROCESSES. 1 99 

in Chapter IV, is always necessary, to a more or less degree, 
in drawn-work. Sometimes oil is the best material — either 
applied occasionally to the dies, or smeared in a thin coat over 
the sheets or blanks, or some of them. Paraffine, applied in 
the same way, is good for tin-plate. Soap-suds works well 
for brass, and there are a variety of special preparations in 
the market. Zinc draws better if warmed as well as lubri- 
cated. 

Iron and other metals are sometimes drawn hot. Among 
the curiosities of heating may be mentioned a method (which 
I think has been patented) of passing a current of electricity 
through the strip of metal as it goes through the press, 
thus heating it locally at the right time and place. 

Cutting-Drawing-Embossing. 

In Fig. 343 are shown in axial section, rear view, a. pair of 
triple-action dies, and in Figs. 344 and 345 a blank and a finished 
box-lid made therein. The action of these is the same as in 
Fig. 331, except that the punch has relatively a longer stroke 
and carries the work down onto the embossing-" matrix " 3f, 
which is fastened at the bottom of a special bolster, B, made 
with an opening at the back through which the work is re- 
moved instead of dropping downward in the ordinary way. The 
object of this is to emboss panels, beads, lettering, or other 
devices upon the bottom of the work, and yet not be obliged 
to knock it up through the die, which is difficult with cylin- 
drical-shaped articles. The removal spoken of is usually per- 
formed by gravity, the press being set in an inclined position, 
so that the work may freely slide out. Sometimes, however, 
an automatic push-out is provided. This is safer, as gravity 
occasionally fails to do its duty at a critical moment. Presses 
built especially for such work usually have a shorter ram- 
stroke than usual, as room is not required between the dies 
for knockout work, and a relatively longer plunger-stroke is 



200 



PRESS-WORKING OF METALS. 



needed, so that the die L may be made unusually thick (to 
give it strength where it bridges across the open space in the 




Fig. 35: 




Fig. 356= 




Fig. izy. 




Fig. 358. 





Fig. 359. Fig. 360. 

bolster), and yet that the punch may descend far enough to 
reach through it and downward to M. The punch itself is of 
course unusually long. 



DRAWING PROCESSES. 



201 



Specimen Drawn-work. 

It is evident that other shapes (looked at in top view) than 
round may be treated by the drawing process. In Fig. 360 
is shown a rectangular sardine-box, whose sides are straight 
and corners rounded to about |- inch radius. This is quite diffi- 
cult to draw, because the action upon the metal at the corners 
is approximately the same as in drawing a cylindrical box with 
the same radius, or \\ inches in diameter, which is very small 
considering the depth attained. There is in such case a violent 
flow of metal, modified somewhat as it extends outward from 
a rounded corner into the two adjacent straight sides. The 





Fig. 361. 



Fig. 362. 




Fig. 363. 

shape of the blank for work of this kind is rather peculiar, the 
corners being very much cut away in comparison with the 
sides, to allow for the great radial stretch of metal at those 
points. The turning up of the sides along near the middle 
thereof is obviously a bending action merely. 

In Fig. 361 is shown an oblong pan with rounded ends, 
which is of somewhat the same nature as the box just men- 
tioned. 

In Fig. 362 is shown a grocers' scoop, which was drawn in 
an irregular die, the flange and a part of the body being 
trimmed off afterward. 



202 



PRESS-WORKING OF METALS. 



In Fig. 363 is shown an ordinary washboiler-bottom, il- 
lustrating a case where no special blank is purposely prepared, 
but where the so-called " well " or depression is drawn in an 
ordinary rectangular sheet of metal, the holding-surfaces of the 
dies of course being large enough to cover it. This system is 
sometimes used in producing certain tin toys, where the two 




Fig. 365. 



JL 



Fig. 366. 



Fig. 367. 



Fig. 364. 

halves of an animal are thus drawn and trimmed and then sol- 
dered together along the spinal column, etc. ; also for various 
other similar shallow work. Its advantage is that no cutting 
dies are needed except for trimming off a part, or all, of the 
flange after drawing, which dies would have to be furnished 
in any case. 

The various utensils shown in Figs. 354 to 359 have al- 
ready been referred to. They represent average tinware, or, 
equally well, the enameled ironware which is coated with a 



DRA WING PROCESSES. 



203 



baked-on porcelain-like skin, and which enjoys a number of 
fanciful names — as christened by the makers thereof. 



Spring-drawing. 

In Fig. 364 is shown a pair of combination spring-draw- 
ing dies, so called, with the blank they cut shown in Fig. 
365 and other stages of the work shown in Figs. 366 and 

367- 



! 



1: 




Fig. 368. 

In Fig. 368 is shown a pair of similar dies, arranged to 
work from a pre-cut blank, and not supplied with cutting- 
edges. The blank, the part-way drawn, and the completed 
work are respectively shown at the side of the dies. In this 
case the combination is one of drawing-embossing. 

Such dies are used in single-action presses, the flange- 
pressure being supplied by the drawing-ring A, which is 
driven up and against the die U by a powerful spring S, work- 
ing against a sliding plate P, through the medium of a series 
of pins B B. The stem D, together with its plate P, nuts N, 
spring S, etc., form a portable device sometimes known as a 
" spring-drawer," which can be screwed into any die adapted 
for it. Work done in this way is generally limited to thin 
metals and in depth to about 1 inch, as the pressure with 



204 PRESS-WORKING OF METALS. 

anything much deeper would be so great as to waste consid- 
erable pressure, the descending ram having, of course, to com- 
press the spring to the same number of pounds as are after- 
ward given out by it upon its ascent — and this in addition to 
its legitimate work. 

Another disadvantage of this strong upward pressure is its 
reaction upon the press-ram and connected parts. This 
sometimes causes the ram of a power-press to "fly up," car- 
rying the shaft around at a higher speed than the fly-wheel 
and making a disagreeable jerk. The remedy -is a closely 
locked clutch or an unusually tight brake. 

A series of rubber disks is in some cases substituted for 
the spiral spring vS. In other cases, especially for shallow 
work, local springs are inserted under the ring A, making 
each die complete in itself and independent of the spring- 
drawer as a separate attachment. The knockout-plate in the 
upper die is driven down by springs, or otherwise, as usual. 

Obviously the ring A, in addition to acting as a knockout, 
performs the function of a blank-holder — the same as does 
the upper die itself in double-action work. 

Blank Dimensions. 

In regard to the important matter of blank dimensions it 
will be pertinent to again quote from my Franklin Institute 
lecture, as follows: 

" It will naturally occur to the student of this subject 
that some easy method is desirable for determining the diam- 
eter of the blank for any given piece of drawn work, espe- 
cially if its dies are to cut, as cutting-edges are expensive to 
make — and to alter, if guessed at and made wrong at first. 
Aside from lucky guessing, somewhat guided, perhaps, by 
analogies from other approximately similar work that dies 
have been made for before, I have in my own practice used 



DRAWING PROCESSES. 205 

three principal methods to obtain this measurement of blank 
diameter. 

"The first of these methods is the tentative one. It is 
the surest, but in many cases the most expensive. It con- 
sists in cutting blanks of as near as possible the right size and 
shape by guess and trying them successively, modifying the 
shape of each to suit circumstances until the proper shape of 
drawn-work is produced. For dies that do not cut this is 
not difficult, as the flat holding-surfaces can be made plenty 
large enough, and whatever gauging arrangements are to 
guide the blank can be put on afterward, when its correct 
proportions are decided upon. In cutting-dies the female 
cutting-ring must be made separately, and left unfinished un- 
til the size and shape are ascertained. The male cutting-ring, 
which forms part of the upper holding-surface, must of course 
be made, but can be left plenty large enough until this trial 
has been completed. 

1 ' The second method referred to may be called the ' grav- 
itative.' It depends for its accuracy upon the principle that 
the thickness of the metal in a piece of drawn-work is the 
same as it was in the original blank, which is in fact usually 
the case. My plan is to carefully weigh the sample piece of 
drawn work which is to be reproduced, and then, knowing the 
weight of 1 square inch of a piece of similar sheet-metal of 
exactly the same measured thickness, to calculate the number 
of square inches necessary in the blank and make its diameter 
to suit this given area. This system can obviously be prac- 
ticed only where a sample of the work is at hand, and where 
the blanks are circular in form. Certain inaccuracies may 
arise in the practice of this method, where there are sundry 
beads, corrugations, etc., near the center of the piece of 
drawn work, which tend to let the metal stretch when the 
punch comes home in the die. Such action is properly em- 
bossing rather than drawing, and stretches the metal thinner 



2c6 



PRESS-WORKING OF METALS. 



in certain places, which, of course, invalidates the accuracy 
of the result. It is, however, often useful for work whose 
contour is simple in form near the central portions, where a 
drawing action does not take place. 

Blank Formula. 

" The third method spoken of may be called the ' mensu- 
rative.' This, too, depends upon equal areas and upon the 
thickness of the metal remaining the same. In the case of 
plain cylindrical work a very simple formula which I have 
worked out for the purpose may be used. This is given in 







rl 


\ 










pS 


^ — r — > 


\ 


v >. 






/ 



i< — r— 
Fig. 369. 

Let (in inches, at middle of sheet's thicktfess) 

d = diameter of cup. a = area of bottom -f- sides. 

h — height of cup. « = area of blank, also. 

r — radius of corner. x = diameter blank is to be cut. 

c = arc of 90 , with radius r. 

a - .785^ + itdh (1) 

*- JUL = i/ r ^^ + %dh • • (2) 

y .78^ y .785 

x — 4/d 2 + a,dh, for sharp-cornered cup (3) 

r' + r" - c — —, about (4) 

2 

2(/ -f- r") — ic = r, about (5) 

x = ( j^d 2 -\- .\dh ) — r, about, for round-cornered cup ; with small 



corner, say where r < — , 
4 



(6) 



Fig. 369, equation 3, for a box or cup whose corner at m is 
sharp, or nearly so, and in equation 6 for a round-cornered 



DRA WING PROCESSES. 



20/ 



box. The latter formula is not theoretically accurate as re- 
gards equal areas, but serves an excellent practical purpose 
where the corner is not of too large a curvature — say with a 
radius not more than one fourth the depth of the cup. The 
diagram given in Fig. 369 is a vertical axial section of a 
cylindrical box or cup, the same as was shown in Fig. 335. 
It is not worth while here to give the working out of the 
formulae, as by a close inspection the figures will explain 
themselves. 




Fig. 370. 

Let (in inches): 

r K , r'\ r m , r u , etc., = radii drawn to axis from centers of gravity of ^-inch 

segments of contour-line. 
s = r l -f- r l + rUi "f" r ' v > etc - ! tnat > s > tn e sum of the radii. 
a = area of bottom -f- sides. 
a = area of blank, also. 

a' = area of one zone whose average radius is r K , r n , or r m , etc. 
x = diameter blank is to be cut. 



a! = 2 r 1 Tt \, etc 

a = 2 srt± — .785.: 

y .izc y .78; 



|A 



(7) 

(8) 

(9) 



.785 r .78 

" In Fig. 370 is shown a system which I have devised for 
ascertaining the area of a piece of drawn-work of irregular 
contour as regards its vertical axial section. This method is 
a graphic one, an exact profile of the work being drawn to a 



208 PRESS-WORKING OF METALS. 

scale of real size, and this contour-line being laid off from its 
axis outward into sections, each exactly i inch long. From 
the centers of these sections horizontal measurements are 
taken to the axis as indicated by r\ r 11 , r ul , r iv , etc. These 
measurements, of course, represent various radii of the piece 
of drawn work in question. If we let the sum of them be 
called s, we then get the very simple formula given in equa- 
tion 9. The reason that just ■§• inch was taken for the length 
of these segments of the contour-line was that it happened to 
reduce the equation to the simple form given, while any other 
length would have made it more complicated. The principle 
here involved is obviously that of the area of any zone being 
its width multiplied by its circumference at a point represent- 
ing the center of gravity of its single cross-section. The 
points marked by r\ r n , etc., are, of course, not accurately in 
the center of gravity of each of the little segments, but they 
are practically near enough so. The same principle occurs in 
this method as in the last-mentioned one regarding places in 
the metal which will stretch thinner when formed to shape, 
like deep beads or other indentations. This trouble may be 
mostly neutralized, however, by bridging over them, so to 
speak, in making the contour-line — that is, by running the 
latter across from point to point of the corrugations, instead 
of following their curves, wherever it is judged that stretching 
will take place. This amended contour is shown at n, n, Fig. 
370, by dotted lines, and on it the segments should be laid out. 

" In making drawn-work whose top view is elliptical in- 
stead of round the formulae above given may be used with 
some modifications. 

" To do this the ellipse is treated separately as regards its 
short and long axes, and values for d are inserted in the two 
equations which would be used for circles that approximately 
coincide with the sides and ends of the ellipse at the termini 
•of its respective axes. 



DRA WING PROCESSES. 209 

" In making rectangular work with round corners some 
idea of the shape of the blank may be obtained by treating 
the corners as belonging to a circle of the proper diameter, 
while the sides of the rectangle, which properly are not drawn 
at all, but only bent to shape, may be treated nearly by actual 
measurement, as in them very little stretching takes place. 
As regards the corners, however, the tentative method is the 
safest wherever it is possible to use it." 

An empirical rule (which has been used for a common 
quality of steel about -fa of the blank diameter in thickness) 
for getting as deep a cylindrical cup as practicable from a 
given blank is to let the cup diameter be |, or 60 per cent., 
of the blank diameter. This obviously might prove too 
much or too little when conditions of thickness and quality 
were changed. 

Trimming Edges. 

In Figs. 351 and 363 it will be noticed that the edge of 
the flange is somewhat irregular, and Figs. 350 and 360 show 
that certain defects in symmetry which start in the flange are 
carried down into the " wall " of the work, often aggravated 
in degree, with the effect of a rough and jagged edge. In 
other words, it is difficult, except with very shallow work, to 
get either flanged or non-flanged articles with edges true 
enough for practical use without a trimming operation. 

Flanged work can be thus trimmed in cutting-dies or with 
rotary shearing-cutters in a " trimming "-lathe. Such lathes 
are usually made so that they will answer also for "spin- 
ning" and "wiring" — sometimes all successively at one 
chucking. 

Flangeless work is usually trimmed in a special machine by 
the use of rotary shearing-cutters. Sometimes, however, a 
" turning-tool " is used, as in a lathe, paring away chips as it 



2IO PRESS-WORKING OF METALS. 

goes through. This process is applied to small thick-walled 
articles, as some sorts of cartridges, etc. 

The chief causes of irregular edges are, first, lack of paral- 
lelism in press beds and rams and in the dies mounted thereon, 
both in original construction and as temporarily induced by- 
distortions due to stresses while working; and, second, lack of 
parallelism, homogeneity of structure, and uniform hardness 
and smoothness in the sheets of metal worked. None of 
these defects can be wholly remedied, and very minute doses 
of them sometimes cause alarming symptoms in the way of 
non-uniform radial distances traveled by various portions of 
the flange. Hence, unconquerable raggedness, especially in 
square and irregular work. 

Roller-spinning. 
The object of spinning is to smooth out the wrinkles, a 
result which may be attained, either before or after trimming, 
by passing a hard roller, mounted in a slide-rest or otherwise, 
over the surface as the article revolves. This may be done 
inside or outside, but in either case the metal of the chuck 
forms a " backing" to take the roller pressure. 

Roller-curling. 

Wiring, as it is usually termed for this sort of work, is in 
most cases merely curling, and is done, after trimming, by 
pressing a grooved roller against the revolving edge. Pans 
as shown in Figs. 354 to 358 have been thus served. Ellip- 
tical and other shapes not round can obviously be treated in 
lathes especially adapted to follow the proper contours. 

Speeds and Pressures. 

In regard to the maximum limit of punch-speed in draw- 
ing we have but few reliable data. The number of strokes 
per minute of drawing presses in commercial use varies say 



DRAWING PROCESSES. 211 

from 8 to 200, with perhaps a rough general average of 50 or 
60 per minute. At these rates the various metals used seem 
to flow properly without tearing fracture, although it may be 
that in some cases a slower speed would produce better re- 
sults. Evidently some systematic experiments are very de- 
sirable. 

But few available data exist, or at any rate have been made 
public, regarding the pressure per square inch necessary for 
holding the various kinds of metal between the surfaces of 
drawing dies. Neither do any proper testing instruments 
exist which will fill all the conditions present. These must 
be originated, and it is certainly desirable that somebody 
should make a series of experiments in connection with this 
matter, as well as in relation to the pressures in general that 
are used in sheet- and bar-metal work. Such experiments, if 
properly performed, are tedious and expensive, but the writer 
hopes at a future time to be able to publish something 
definite upon the subject. Some fragmentary experiments 
which he made a few years ago show about 200 pounds per 
square inch for holding the flange of a small milkpan, over 
300 pounds upon a blacking-box in one case and nearly 500 
pounds in another. One such box, with less than 1^ square 
inches of drawing-surface, stood over 4000 pounds without the 
bottom being punched out, showing that in such shallow work 
there is often a great excess of flange strength. In general, 
for small tin-plate work, etc., the pressure will probably run 
between 200 and 400 pounds. 

The greatest possible plunger-pressure that can be used in 
any given case, without breakage, is, of course, measurable by 
the tensile strength of the cross-section of the work at the 
smallest diameter of the punch. This strength is obviously 
found by multiplying the circumference of the work at that 
point by the thickness of the metal (both in inches) and by its 
ultimate tensile strength per square inch. Or, P := SIVT, 



212 PRESS-WORKING OF METALS. 

our old formula with a new application, P being pounds, W 
width of metal (circumference), T thickness of the same, and 
5 strength in pounds per square inch — in this case tensile. 

If the plunger of a press will give this pressure (counting 
its maximum work), and the ram nearly or quite as much 
more, and all without too much springing, it is suited for its 
vocation. 

Kinds of Presses Desirable. 

In regard to the kinds of presses used for such work the 
general motion required has been before described. The 
plunger motion is almost always produced by means of a 
crank and pitman. The ram motion also is sometimes ob- 
tained this way in the case of certain kinds of shallow work, 
especially in brass factories. The " dwell " for the purpose 
of holding the flange of the work is obviously in such case but 
an approximate one, but if the metal is not too thin it seems 
to answer the purpose in the cases referred to. The majority 
of drawing presses are arranged to work the ram during its 
downward stroke by means of cams. These, if properly made 
with enormously strong shafts and rollers, with amply large 
bearing-surfaces and of proper material, are very efficient and 
durable. The lifting of the ram is sometimes positively done 
by cams, and sometimes by non-positive devices, such as 
springs and weights, or steam-, air-, or water-pistons working 
in appropriate cylinders, etc. Any of these devices, if prop- 
erly designed and adapted to the speed of the press, are suffi- 
ciently good for the purpose. In cases where the ram carry- 
ing the upper die, or blank-holder, is reversed, doing its 
clamping in an upward instead of a downward direction (as is 
the case in some large bottom-ram presses), the direct action 
of gravity is used to return it. This gives excellent results, 
and an exceedingly simple construction can be obtained. 
Another device which has come into rather extensive use 



DRAWING PROCESSES. 213 

consists essentially of a system of toggle-joints intervening 
between the ram and the press frame, which hold the ram 
securely clamped, with its die against the flange of the work, 
without bringing a running-pressure upon the shaft and roller- 
bearings, as is the case with cam-presses. This is obviously 
an advantage, but there is considerable difference of opinion 
among press makers and users as to whether any such advan- 
tage compensates for the additional complication required, espe- 
cially after several years' wear has taken place. In general, it 
may be said that any of the plans mentioned are practically 
good enough if properly designed. 



214 



PRESS-WORKING OF METALS. 



CHAPTER X. 



RE-DRAWING PROCESSES. 



Re-drawing. 

FOLLOWING the drawing process proper, as described in the 
last chapter, is the process of "deepening," "reducing," or 
" re- drawing, " by any one of which terms it is designated. 
It depends in general upon the same principles, but differs 
somewhat in detail. The chief difference is that instead of 
drawing a comparatively shallow cup-shaped article from a flat 
blank it deepens the cups already made into other and deeper 
cups, at the same time reducing their diameter. 

In Fig. 371 is shown, in vertical axial section, a pair of dies 
for performing such operations. In Fig. 372 is a section of a 




Fig. 372. 



Fig. 374. 



Fig. 371. 




Fig. 375. 



cup-shaped piece of work, which, by the way, is often tech- 
nically called a " cup" by the makers of cartridges and such 
like articles, its name after re-drawing being a "shell." It 
has previously been drawn from a blank, as described in 
Chapter IX, and is placed in a recess in the lower die L, made 
to fit it, so as to guide it centrally into place. The upper die 
U is of such a diameter as to fit inside of it, the rounded cor- 



RE-D RA WING PR O CESSES. 



215 



ners at r and r, Fig. 371, being made of such curvature as to 
fit each other. Successive stages, during the progress of the 
punch at one down stroke, of the work as thus re-drawn are 
shown respectively in Figs. 373, 374, and 375. The rounded 
corner of the drawing-punch r' obviously governs the corner 
of the finished work, as shown by the same letter. 

After the first re-drawing the deepened cup or tube can 
of course be again drawn, with another reduction of diameter, 
and then again, and so on ad infinitum, within certain practi- 
cal limits. These limits are chiefly governed by the condition 
of the metal, which tends to harden in more or less degree, 
just as it does with other forging operations. With iron, 
steel, brass, copper, etc., annealing is necessary after each two 
or three draws. With such annealing, however, almost any 
increase of length can be obtained, as is shown in the case of 
an ordinary cartridge-shell, penholder-tube, or similar article. 
A series of successive stages of such re-drawing are shown in 
Figs. 376 to 380. In the case of tin-plate or other metal 



D D 



Fig. 376. 



Fig. 377. 



Fig. 378. 



Fig. 379. 



Fig. 380. 



which cannot be annealed without spoiling the coating, not 
more than one or two re-drawings can usually be made ; and 
then the metal is apt to be so brittle near the edge, where 
most of the flow has taken place, as to render it unfit for 
other bending operations, such as curling, etc. By one 
re-drawing it is practicable to obtain a tin-plate cup or box of 
a depth about equal to its own diameter. Here, again, the 
proportions depend, of course, upon the quality of the metal 
and its thickness in relation to its diameter. 

A somewhat empirical rule for steel shells whose thickness 



2l6 



PRESS-WORKING OF METALS. 



approximates say ^ of their final diameter is to reduce the 
diameter from 20 per cent to 30 per cent at each draw. As 
the literature of this subject increases we shall doubtless find 
available more numerous and more definite rules and tables 
which will eliminate many of the " cut-and-try " methods 
now so prevalent. 

In Fig. 381 is shown a square steel box with rounded cor- 
ners, as drawn in its first operation. In Fig. 382 is shown a 




Fig. 381. 





Fig. 382. Fig. 3S3. 

second operation, as it was re-drawn, and in Fig. 383 a third, 
making it into a complete elevator-bucket. In this case the 
last operation was not, properly speaking, drawing, as the edge 
was trimmed and at the same time turned upward by being 
forced through a die, without reducing the diameter 0} the 
body, and therefore with no chance to use a blank-holder. 
This is very difficult work to make, as the writer discovered 
some years ago when developing for a client various sizes of 
these buckets, as a new article of manufacture. 



Inverted Re-drawing. 

In Fig. 384 is shown a pair of re-drawing dies, where the 
cup, Fig. 385, is placed over the lower die in an upside down 



RE-DRA WING PROCESSES. 



217 



position. It is therefore turned partially inside out in being 
brought to the form shown in Fig. 386. In Figs. 387 and 
388 are shown subsequent deepenings, which will explain 
themselves. With plain shapes of this kind there does not 
seem to be any particular advantage in thus reversing the 
work, although in some cases it is desirable for special reasons. 
One disadvantage, where the reduction in diameter is small, 
is that the lower die must be thin radially, and is therefore 
liable to burst should an extra thick sheet get in. 

An amusing, though annoying, circumstance connected 
with this last-named process is that after being in common 
use in various factories for a number of years somebody pat- 




Fig, 385. 



Fig. 386. 



1 



Fig. 384. 



Fig. 387. 



Fig. 388. 



ented it. It is true we cannot expect the Patent Office offi- 
cials to know everything that is happening in the mechanical 
world, but this fact suggests that possibly an occasional tour, 
at the Government's expense, among such plants belonging to 
the great industries of the country as pertained to each visit- 
ing examiner's particular kind of work, would be an excellent 
investment of the people's money. 

The case just mentioned is not unique, there being frequent 
blunders of the same sort. A number of others might be 
cited which pertain to sheet-metal work. One of these patents 
is upon cutting sheets, as already mentioned in connection 
with Figs. 267 and 268, for another old process. 



218 PRESS-WORKING OF METALS. 

In Figs. 389 to 391 are shown the different stages of the 
work performed in a similar die to that last described, but 
with the difference that the cup, Fig. 389, was left with a 
flange upon it in its first operation. This flange could not, 
obviously, be very wide, there being nothing to prevent its 
wrinkling as it gradually crawls inward and upward upon the 
lower die. The process is sometimes useful with thick metals 
and small diameters to produce such work as the "castor 
socket/' Fig. 391, in the final operation. 

Broaching. 

A modification of a deepening operation proper is shown in 
Fig. 392, where the "broaching" process is combined with 
the re-drawing. The word broaching has here a very different 
meaning from that given it by the machinist, who applies it 
to the process of forcing a piece of male work through a lower 
cutting-die, or pushing a cutting-punch through a hole in 
female work, thereby shaving it to a given size, and really 
performing an operation analogous to planing or slotting. In 
cases where he uses male or female broaching-cutters having a 
series of teeth following each other, and each taking off its 
own chip, his work more nearly resembles milling. 

In relation to sheet-metals the word broaching means 
smashing the work thinner by forcing it through a space be- 
tween the punch and die which is too small for it. This in 
itself is, of course, very similar to some kinds of tube-drawing, 
which again is the same as wire-drawing, if we imagine the 
mandrel to be a part of the tube. In the case in question a 
reduction of diameter is being made at the same time as the 
thinning of the metal is taking place. This is much practiced 
in cartridge-drawing, especially where it is desirable to keep 
the end or bottom of the work of the original thickness, as 
shown in the picture. When done, the bottom remains of as 
much greater thickness than the sides as happens to be 



RE-DRAWING PROCESSES. 219 

required, and as has been arranged for in choosing the thick- 
ness of the sheet. In small work of this kind the use of a 
blank-holder, or upper die, U, is abandoned after the first one 
or two draws, as the metal is reduced so little in diameter in 
proportion to its thickness that the wrinkles have no chance 
to form. Even if incipient wrinkles do form they are quickly 



n 



Fig. 389. Fig. 390. Fig. 391. 

crushed out again as the metal is squeezed somewhat thinner. 
In this, as in all drawing, however, the wrinkles must never 
be allowed to get big enough to fold over upon one another. 

Vee Blank-holders. 

In some large work, such as various kinds of pans having 
considerable taper, a kind of upper die termed a " vee blank- 
holder" is sometimes used in a re-drawing operation. This 
blank-holder outside is of the same shape and size as the 
punch which drew the first operation, but is cylindrically 
hollow inside, for the punch of the second operation to pass 
through it. Thus the wrinkles are held from forming in a 
conical zone constituting the upper part of the body of the 
future completed pan, rather than in a flat flange, as is usually 
the case. 

A press is said to have been built several years ago with a 
series of these blank-holders inside of one another, each being 
as above — a ring with its exterior periphery in the form of a 
truncated cone. Outside of these was an ordinary flat blank- 
holder, which descended first as usual. The outer ring de- 
scended next, drawing a depression in the blank so shallow as 
not to have body-wrinkles. This, of course, acted as a 



220 PRESS-WORKING OF METALS. 

punch, its central aperture surrounding the nest of other rings, 
not interfering with its functions for fiat-bottomed work. It 
then stopped and served as a vee blank-holder for the next 
contained ring, which, in the same order, performed the same 
functions respectively. Thus all acted in succession, the 
result being a conical pan without wrinkles or need of spin- 
ning, all parts of its surface having been "held" as much as 
necessary at all stages of the operation. 

This machine probably had no relatives or descendants. 
It was theoretically very beautiful in principle, but the prac- 

"1 



Fig. 392. Fig. 393. Fig. 394. 

tical difficulty of driving all the rings with just the- right 
motions, and of keeping them in order, together with the 
complications incident to changing frequently from one-sized 
pan to another, must have soon ended its career — and with- 
out much hope of posterity. For several billions of one-sized 
pans the scheme would be a good one, however. 

RlM-FORMING. 

In Fig. 393 is shown the first operation (being ordinary 
drawn-work), and in Fig. 394 the second operation, of what is 
known asa " rim-cover," such as is used as a lid for pots and 
other utensils. The bead or rim a has been " bulged " out- 
ward by the simple process of pushing the top down with a 
plain concave die, the lower edge of the metal being properly 
confined in a lower die. This is, of course, not a process of 
drawing at all, but is simply given here to illustrate an inter- 
esting operation following the work of the drawing-press. It 
is usually necessary to trim the edge true before bulging, 
especially if the depth is considerable relatively to the diam- 
eter. Otherwise the ragged edge causes irregularities in the 
rim. 



re-drawing processes. 221 

Neck-reducing. 

Another useful after-process applied to a deep-drawn shell, 
of comparatively thick metal, of the shape of Fig. 395 is prac- 
ticed by reducing the upper ends and thus forming it into the 
similitude of a metallic bottle, as in Fig. 396. This reduction 
is sometimes done entirely by spinning, but can also be done 
by a series of dies forced over the neck one after another, the 
body of the work being properly confined. Some cartridge- 
shells are reduced in this way at the open end. In Fig. 397 





A 



Fig. 395. Fig. 396. Fig. 397. 

is shown a somewhat similar reduction of the neck at a. 
together with the bulging out of a part of the body at b, thus 
forming a pitcherlike utensil, as shown. This bulging out 
ward might be done with certain forms of expanding dies, or 
with a fluid punch, as described in Chapter VII. It is, how- 
ever, usually performed by a spinning operation from inside. 

The Speed and Pressure 

required for re-drawing are so nearly the same as for primal 
drawing, mentioned near the end of Chapter IX, that no fur- 
ther data need be here given. 

Presses Most Suitable. 

In regard to the kind of presses best adapted for the 
reducing and deepening operations just treated of it may be 
said that such machines for many of the processes in ques 
tion are usually supplied with single-action rams, the chief 
characteristic being an unusually long stroke. Of course, 
where the stroke and power are sufficient, any ordinary press 
will do, and no very great accuracy is required. In some 
cases such presses are made with an abnormally long stroke, 



222 PRESS-WORKING OF METALS. 

arranged to adjust to any amount desired, after the manner 
of a planer-table, the ram being driven through the medium 
of a rack, screw, or other suitable mechanism. The horizon- 
tal-ram type of press is frequently used instead of the vertical,, 
especially for large cartridge-drawing and tube-making. 

Drawing, Prophetically. 

The future possibilities of the interesting process of draw- 
ing and re-drawing metals seem to me very great. Much has 
been done in comparatively recent times in the way of devel- 
oping the various operations involved. 

It is a somewhat curious fact that small thin steel tubes for 
bicycle- frames are now drawn in 12- or 15 -feet lengths, start- 
ing with a thick flat blank but a few inches in diameter, and 
that this seemingly tiresome process can commercially com- 
pete with the simpler plan of drawing down a hollow ingot. 

In the direction of general bigness we can, even now, 
manage articles as large as soda-water fountains and kitchen- 
boilers, drawing them cold, by the processes above described, 
from ordinary flat sheets. To draw large steam-boilers in 
the same way would be only a matter of enormous first 
cost for the plant. Many irregular-shaped articles are also 
now drawn, such as wheelbarrow-bodies, sinks, mangers, etc. 
These processes simply need amplifying. to produce bath-tubs 
and boats. How large objects it will pay to attempt in this 
way I will not venture to predict. The commercial and me- 
chanical sides of the question will no doubt, as usual, adjust 
themselves finally into a condition of stable equilibrium. 

In general, it may be said that the beautiful processes in 
question have already proved themselves boons to mankind, 
especially in the way of cheapening household utensils, and 
putting more and better ones within reach of the masses. 
The future will doubtless see further and still more wonderful 
developments. 



COINING PROCESSES, 



223 



CHAPTER XI. 



COINING PROCESSES. 



Drop-forging. 

The process of coining, as has been indicated in earlier 
chapters, is analogous to drop-forging; or pumping melted 
metal into a type-mold ; or squeezing a piece of soap or clay 
in the palm of one's hand ; or molding a pat of butter. In it 
we see illustrated the principle of the flow of solids, even more 
vividly than in the drawing process. 

In Fig. 398 is shown, in vertical axial section, a pair of 
ordinary drop press dies, arranged for drop-forging a small 




UlNi. 'HI 



Fig. 399. 



Z. 




Fig. 398. 



Fig. 400. 



Fig. 401. 



hand-wheel, as shown in axial section in Fig. 400 and in top 
view in Fig. 401. It is possible to do such work as this cold 
where copper, lead, and other soft metals are used. In prac- 
tice such dies are more often employed for iron or steel, 
heated almost to a white heat. In Fig. 399 is shown a blank 
from which the wheel is made, which may be of any appro- 
priate form. In this case it is merely a round punching, made 
from flat bar-iron. The process is, of course, simply one of 



224 PRESS-WORKING OF METALS. 

molding, the die L being rigidly secured to the bed of the 
press and the die U to the ram. The latter descends from a 
considerable height, and with a force far greater than is usually 
employed in sheet-metal work. 

A distinguishing characteristic of freshly drop-forged prod- 
ucts is the irregular little fin, surrounding the work like a halo 
at a a. This is evidently due to the surplus metal creeping 
out between the dies — -the only path of escape open to it. It 
is true this fin might not occur, but it generally does. Its 
absence is attainable only by the blank being placed exactly 
in the right position, remaining there during the blow, and 
containing exactly the right amount of metal. These fins, as 
before intimated, are always present in some degree, but are 
trimmed off afterward in a "trimming-press," in which are 
mounted dies that are, of course, nothing but ordinary cutting- 
dies — with the punch hollowed out, as far as practicable, to fit 
the upper surface of the work. Obviously, by this process such 
articles only can be made as will deliver freely from the dies, 
by reason of having considerable taper and no high vertical 
walls. Extremely irregular contours present no special diffi- 
culties. 

The practical applications of the art in question are far too 
numerous to be scheduled here. By it thousands of small 
tools and parts of machinery, hardware, cutlery, etc., are 
rapidly made, with the uniformity of punched-out work, but of 
far better quality as regards smoothness and density. Most 
of them, moreover, are of rounded-up forms, so to say, which 
could not be made at all from flat sheet-metal with punching 
dies. Such forgings are usually better than the best hand- 
made forgings, as well as vastly cheaper and more uniform. 
They are often cheaper than castings of like form, and for 
most purposes a great deal better. 



COINING PROCESSES. 



225 



Coining Coins. 

The process of coining, as employed for manufacturing 
medals and metallic money, embodies the same general prin- 
ciples as drop-forging work, but is carried out very differently 
in detail. Furthermore, the metals used are generally worked 
cold, and there is much more uniformity in the general design 
of the product than in the drop-forging art, whose products 
embrace almost every conceivable kind of article adapted to 
the processes employed. 

In Fig. 402 are shown, in vertical axial section, a pair of 
coining-dies, U and L, together with their "collar" C, such 
as are used in the mints of all the principal civilized nations 
of the earth for stamping the coins of the realm, from so-called 
" planchets " or "milled" blanks, as shown in axial section 





Fig. 402. Fig. 403. 

in Fig. 406. These dies are shown in open position, ready 
for the planchet to be fed into them by sliding it over the 
face of the collar and allowing it to drop into the same and over 
the lower die. In Fig. 403 the same dies are shown in closed 
position, as when giving pressure to the embryo coin. In Fig. 
404 they are shown when the upper die has risen out of the 
way and when the lower die has risen in its collar to eject the 
coin ; or, as is often the case with an alternative device in 
press motions, when the collar has descended for the same 
purpose, the lower die remaining stationary. 



226 



PRESS-WORKING OF METALS. 



Ill Fig. 405 is shown, in edge view, a blank as punched by- 
ordinary round. cutting dies from a strip of metal of the proper 
thickness; and in Fig. 408 an enlarged partial section of the 
same appears. At a b are shown, exaggerated, the char- 
acteristic rounding on one side and burring on the other 
incident to all punching operations. These, however, do not 
signify, as the "milling " machine kindly takes care of them. 

In Fig. 406 is shown in section, as before mentioned, and 
in Fig. 410 in partial section a planchet which has been made 
from a blank by the " milling process," so called. This con- 
sists of rolling the edges in a special machine, the radial com- 



1 n "iim 

Fig. 405. 





Fig. 407. 



" > 



Fig. 404. 



Fig. 406. 



Fig. 408. 



pression thus obtained upsetting or thickening them into the 
form shown, while at the same time the corners are rolled down 
to a rounded shape, preferably more like c than d. In Fig. 
407 is shown the face of a finished medal which has received 
upon both sides at once reversed impressions from the respec- 
tive upper and lower dies employed. 

In some cases a coin or medal is " reeded," or fluted upon. 
the edges, as is the case with our American silver and gold 
coins, the so-called reeding consisting of a number of fine 
teeth, or cogs, running parallel with the axis of the coin. 
These are formed by fluting the internal surface of the collar 
C, which is usually made very slightly conical, to facilitate 
easy deliverance. 



COINING PROCESSES. 227 

Jt is evident that in this kind of work, as well as in 
drop-forging, there is a tendency to produce unwelcome fins, 
should there be a surplus of metal to the slightest degree. 
These fins of course tend to form as at e and f, Fig. 409, in 
the only place available for the metal to escape, which is in the 
joints between the dies and collar. Manifestly they must be 
avoided, and great care is therefore taken, for mechanical as 
well as financial reasons, that the weight, and consequently 
the approximate mass, of metal in all the planchets shall be 
uniform, at least to within a very small limit of error. Even 
with this accuracy of bulk there would sometimes be minute 
fins, especially as the dies cannot be depended upon to always 
come exactly the right distance apart, were an attempt made 
to produce perfectly sharp corners at c and d. For this rea- 





Fig. 410. Fig. 411. 

son, as well as for convenience and beauty in the coin, these 
corners are rounded, an attempt being made to leave them of 
nearly as great a radius of curvature as was given to them by 
the milling process. This, of course, can only be done by not 
pressing the planchet hard enough in the middle to make the 
edge flow out violently and force itself into the interstices of 
the mold, as in Fig. 409. Fortunately, with the metals ordi- 
narily used, this can be done successfully, and yet a suffi- 
ciently deep, sharp, cameo impression obtained upon each 
face of the coin. The changing conditions above referred to, 
however — viz., some slight difference in bulk, a non-uniform 
descent of the upper die owing to springiness in the machin- 
ery, and certain trifling variations in the density of the 
metal — cause a different amount of edgeward flow. Conse- 



228 PRESS-WORKING OF METALS. 

quently upon some coins, and upon one face more than the 
other of some certain coin, and perhaps at certain places around 
the edge of a given coin-face, the metal will flow outwardly 
scarcely at all, thus leaving a considerably rounded corner at 
c. At other times and places the circumstances mentioned 
will cause a greater flow edgeward, with the result of a much 
sharper corner, as shown at d. The constant effort of the 
coiner, however, is to prevent d from ever becoming entirely 
sharp. A casual examination of any new coin will show, 
without a magnifying-glass, these inaccuracies as to the rela- 
tive sharpness of corners, even in different places upon the 
same coin. 

Within a short time past, and since the production of 
aluminum has been so wonderfully cheapened, it has become 
fashionable to coin this metal into medals of all imaginable 
designs, and all degrees of beauty and ugliness. Some of the 
makers of these have attempted an excessively deep cameo 
effect. The metal, however, has proved itself too prone to 
flow wheresoever it listeth, with the practical result of a finned 
edge like Fig. 409, the metal near the periphery not proving 
itself to be a sufficiently strong hoop to hold in against the 
radial flow outward started by the central expanding forces. 
The makers, who attempted but a small production, dressed 
the obnoxious fins off in a lathe, which, of course, was a slow 
and wasteful process. In one case these difficulties were 
brought to the attention of the writer, Avho suggested the use 
of a planchet made thinner around its edge instead of thicker, 
and also considerably tapered off, as in Fig. 411. Such a 
shape is easily made in a pair of special dies after cutting the 
blank ; . or in the sheet, before cutting the same, by compress- 
ing dies set in a gang with the cutting die, on the "succes- 
sive" plan, so as to produce the blanks at one operation. 

This form of planchet proved successful, as the surplus 
flow from the center was, by the time the impressions were 



COINING PROCESSES. 220, 

made, none too great to properly fill the edges of the mold — 
by which term is meant the group formed by the dies and 
collar, closed as in Fig. 403. In general, as the flow can be 
outward easier than inward, there should always be thickness 
enough in the middle to suit the particular coin being made. 

Riveting. 

Riveting is really a coining process, inasmuch as the 
metal is caused to flow from the old shape of the rivet-body 
(usually cylindrical) to a new and different shape of larger di- 
ameter, forming the head, which is approximately conical or 
hemispherical. The body also is oftentimes upset, that it 
may closely fill the hole, and thus a coining-flow is set up 
throughout the structure. Sometimes the metal is hot and 
sometimes cold. In any case the details of riveting are too 
well known to need further description herein. It should be 
mentioned, however, that there is in modern practice a ten- 
dency to more and more substitute a single press-stroke for 
the numerous hammer-blows- formerly so much used, espe- 
cially in hot work, as boiler-riveting, etc. 

Compressing Plastic Substances. 

In Fig. 412 is shown a pair of dies and a collar, such as is 
used for making the ordinary medicinal tablets, or disk-shaped 
pills, shown in Fig. 413. These work precisely upon the same 




Fig. 413. 

principle as do the dies in a coining-press, and are sometimes 
made of other shapes than round, such as square, triangular, 
etc. The material in this case is usually a dry powder which 



23O PRESS-WORKING GF METALS. 

adheres by compression. Any fins that may occur are so 
fragile as to rub off in handling, and are not noticed. 

Soap-presses also work upon precisely the same principles 
above described, and all the cake-soap in common use is 
simply the product of coining the crude pieces of irregular 
shape, which are usually placed in the lower die by hand. 

The same process is sometimes used for compressing cakes 
of salt and other materials, usually in the form of rectangular 
bricks. The ordinary brick press of commerce is another 
illustration of a coining apparatus, the dies or molds being 
usually set in gangs of several together in a row. That form 
of brick press which uses dry powdered clay is almost as 
elaborately built as is a smaller coining press, but is, of 
course, relatively immense in its proportions and strength, as 
very great pressure is required to properly compact the clay. 

Tube-squirting. 

An interesting modification of coining proper is seen in 
the process of making from soft metal (cold) the thin- 
walled, thick-ended, collapsible tubes used for painters' colors, 
toilet-pastes, and a variety of other purposes. Not only do 
these tubes find their active vocation in squirting forth these 
semi-liquid substances, when pressed to do so, but they are 
themselves squirted into existence, so to speak. 

This process consists in squeezing a thick flat disk of metal 
so tightly in a deep female die that its particles flow outward 
and upward around the punch. This is made enough smaller 
than the die to allow room for the desired thickness of wall. 
The result obtained is evidently an amplification of the Jin 
shown at e, Fig. 409. Any desired shape of neck can obvi- 
ously be formed at the same time, and a proper hole can be 
perforated therein. Such tubes are usually made, a consider- 
able number at a time, in gang-dies, set in a hydraulic press. 

Somewhat akin to the process just described is the squirt- 



COINING PROCESSES. 2 1 1 

ing of continuous lead and tin pipes through a die and 
around a mandrel, from an annular mass of metal to which 
enormous pressure is applied. 

Speed and Pressure. 

The speed employed in the operations we have been con- 
sidering should not be too fast to obtain the fine impressions 
usually required. It is probable that the ordinary speed of a 
drop press ram might in some cases give the metal scarcely 
time enough to flow, but there is no difficulty in practically 
running such machines at a speed of from 100 to 200 strokes 
per minute, 120 being the usual standard for small coins in 
the United States mints, and 100 for the larger ones. Such 
limit as exists seems to be a matter of press-jerking rather 
than slow-flowing. In a machine designed by the writer (see 
Fig. 138, page 68) the customary 6" feeder-stroke and 1^" 
ram-stroke were replaced with strokes of £" and £", respec- 
tively. The result was a speed of 200, with scarcely percep- 
tible jar or noise. 

Regarding the pressure required for ordinary coining but 
few data are available. The force applied to any given coin, 
however, of course considerably exceeds the ultimate com- 
pressive strength of that particular piece of metal, otherwise 
it would not flow. The approximate pressures supposed to 
be used in the U. S. mints are as follows: For dimes, 30 
tons; quarter-dollars, 60 tons; half-dollars, ioo tons; dollars, 
1 60 tons — all of 2000 pounds each. 

Presses Used. 

The presses used for medals, of which but small quantities 
are usually required, are generally hand-fed, and are either of 
the screw- or toggle-driven type. Drop presses sometimes 
come into play, but are more difficult than others to keep in 



232 PRESS-WORKING OF METALS. 

a condition conducive to the accurate working and mainte- 
nance of dies — to say nothing of their too fast speed. 

For regular coinage in government mints, and in some 
cases in the factories of medal- and badge-makers, automatic 
presses are used in which the planchets are simply piled by 
hand into a long vertical tube, the machine doing the rest 
upon its own responsibility. 

In general, coining machines must be of much stiffer de- 
sign than the average run of presses, and of comparatively 
enormous power. They are usually made with two straight 
columns, placed as near together as possible, and with very 
deep cross-members — all with a view of preventing "springi- 
ness" to the greatest possible degree. 



PRESS-FEED ING. 233 



CHAPTER XII. 

PRESS-FEEDING. 

Definitions. 

The terms " feed " or " feeder" or " feeding-attach- 
ment " refer, in this connection, to the various devices that 
are sometimes mounted upon presses, the object of which is to 
move into place between the dies the material to be worked 
thereby. The word " feed " is also used to designate the 
motion of the material, as well as the device by which such 
motion is produced. " Feeding " applies to the operation of 
supplying " work " to the press and dies, whether in the 
form of the original sheets or bars of commercial materials, 
as a primary operation, or of partially made articles as sec- 
ondary and tertiary operations, etc. This feeding may be 
manual or mechanical. In the latter case it is usually auto- 
matic. 

Hand-feeding. 

The primitive, and by far the most usual, method of feed- 
ing a sheet or bar of metal to a press is by hand, the opera- 
tor's muscles sometimes being guided and assisted by certain 
fixed gauges, as heretofore mentioned, although it is often 
the case that he depends upon his eye or hand alone. In 
some cases, particularly in heavy punching work, the holes 
to be punched are marked upon the sheet or bar with white 
paint, usually through a stencil. In other cases the centers 
of such holes are marked with a center-punch. In the latter 
case the punch terminates in a small conical point, projecting 



234 PRESS-WORKING OF METALS. 

in the line of its axis, which enters the impression previously 
formed by the center-punch. Such feeding is adopted only 
for slow-going work, where there is time to properly adjust 
it. It requires, moreover, constantly vigilant attention on 
the part of the operator, and does not always produce very 
accurate results, especially when the press ram runs continu- 
ously, as is often the case. The feeding of tin-plate to cut- 
ting or combination dies is usually performed by hand. This 
is naturally the case, as the sheets are of small size, and not 
well adapted for automatic devices, because they would have 
to be replaced too often. It is earnestly to be hoped that 
our modern inventors will soon supersede the antiquated 
methods used in producing this useful metal by some process 
that will give it to us in long strips from a reel. We can 
then double or treble the speed of our press-work upon it. 

In connection with hand-feeding the melancholy fact 
must be looked in the face that many of the best press-oper- 
ators in this and other lands may be found with mutilated 
hands, or, as past-masters of the art, with no hands at all. 
There seems to be a peculiar fatality in this respect, which 
perhaps is not so strange after all, when we consider the enor- 
mous number of operations performed by these faithful men 
and women and boys and girls, in some cases amounting to 
10,000, 20,000, and (with certain work) even over 100,000 
per day of ten hours. The worst danger is not usually, as 
might be supposed, with " continuous feeding," but occurs 
in cases where a power press is stopped each time by an 
automatic clutch, and started by the operator with the usual 
foot-treadle. The dies and the gauging therein are often so 
arranged that his hand must pass between the upper and 
lower die each time, to locate and remove the work. He is 
apt to get into the habit of moving his foot and his hands 
rhythmically with each other, which is all right so long as his 
attention is not attracted by pretty girls passing the window, 



PRESS-FEEDING. 235 

a pack of fire-crackers exploding in the street, or, worse, by 
an accidental failure of the press ram to stop as usual at the 
top of its stroke. 

It is too often the case that when some of these things 
happen a die descends before the fingers are out of the way, 
and that one or more of them is crushed or cut off. It has 
so far seemed to be impossible either to make presses that 
will not get out of adjustment (usually either through the 
failure of proper attention or from lack of lubrication), or 
to prevent operators from becoming careless. The only real 
remedy is to so design dies, with automatic and other safe- 
guards, that it is impossible for any part of an operator's per- 
son to enter between them. It is, for instance, perfectly prac- 
ticable to make a stripper so deep as to inclose a cutting punch 
entirely at all points of its stroke, to extend so low that no 
fingers can enter beneath it, and to be so thin at its bottom 
edge as not to be in the way of feeding. With forming dies, 
etc., there is somewhat more difficulty, but nothing which 
cannot be overcome with sufficient ingenuity. 

Such providing of safeguards has been carried out in the 
form of a thoroughly practical system in certain factories 
known to the writer, but there seems to be a lamentable lack 
of interest in the matter by employers generally, as well as 
by the employes, who suffer the most. The fact is that a 
perfect system of such safeguards is difficult to install, and is 
apt to be quite expensive. The experience of press- and die- 
makers is that their customers are not willing to pay for more 
than enough tools to actually do the work, the extra appli- 
ances required for safety not being absolutely necessary. In 
many cases such devices are difficult to design, as any par- 
ticular die may perhaps require a new system contrived es- 
pecially for it. For gradual improvements in this important 
field it is to be feared we can only look to the future, in the 
same way as we must for the expensive safeguards needed to 



236 



PRESS-WORKING OF METALS. 



protect our much smashed-up railway employes. Public 
sentiment, and its consequential legislation, doubtless will, 
after a while, do these things so necessary to an era of decent 
civilization. 



Roller- feeding, 

• 

Automatic roller- (or roll-) feeding is mostly applicable to 
very long sheets or bars, especially to those which are thin 
enough to be wound upon a reel. In this case an operator 
can attend to a number of presses at once, only replacing the 
rolls of material as they are exhausted. For such work a pair 
of " feed-rolls," operating after the same manner as a clothes- 
wringer, is usually employed, or sometimes two pairs, work- 
ing " in time " with each other, one on each side of the dies. 
This double arrangement is in order that no unfed places shall 
occur at the ends of the sheet. The feed-rolls mentioned 
have, of course, an intermittent motion, pushing or pulling 
the material forward while the dies are out of contact, and 
stopping while the work is being done upon it. 

In Fig. 414 is shown a single roller-feed mounted in a wide 
press in which is also mounted a long gang of dies. In this 
way the so-called perforated metal, or paper, is produced, 






Fig. 414. 



Fig. 415. 



Fig. 416. 



although double-feeds are more frequently used for this pur- 
pose. The presses, in this and some following views, are 
shown partially broken away — particularly at the fly-wheel 
and at the legs or pedestal. 



PRESS-FEEDING. 237 

In Figs. 415 and 416 are shown double roller-feeds, where 
the strip of work is both pushed toward the dies and pulled 
away from them on the other side. It will be noticed that; 
in the first two feeds mentioned the pitmans connecting the 
adjustable crank upon the press shaft with the rolls, and the 
rolls with each other, respectively, are pivoted to levers upon 
the roll shafts. In the last-named picture the pitmans carry- 
racks which drive by meshing into spur gears. The inter- 
mittent motion is obviously obtained by pawls and ratchets. 



Reel-feeding. 

Another popular device giving an intermittent linear mo- 
tion is known as a" reel-feed." This is often used for thin 
metals, with single punching, or where a number of pieces are 
to be cut from the sheet at once, providing the scrap remains 
strong enough to hold itself together after being perforated. 
This scrap is wound upon a reel atone side of the machine as 
the uncut metal is unwound from another reel upon the other 
side. The spacing of the feed is in this case performed by a 
finger-gauge, which automatically enters one or more of the 
cut perforations, making them do their own gauging, and 
then rises out of the way whilst the feeding occurs. It of 
course enters again before the arrival of the latest edge of the 
hole which is to abut against it. The pulling reel attempts 
an excess of motion, the pull yielding when the fixed distance 
has been moved through, by means of a friction-slip arrange- 
ment. The supplying reel is, of course, controlled by a brake 
against too rapidly delivering. 

In Fig. 417 is shown a reel-feed, mounted upon a double- 
action crank press — together with strip of brass which is beino- 
fed. In this case the feeding is from back to front, but it is 
often arranged in a right-and-left direction. It is also just as 
likely to be equipped upon a single-action press 



2 3 8 



PRESS-WORKING OF METALS. 



Grip-feeding. 

Another form of linear feeding is what may be called the 
step-by-step, where the sheet of material is intermittently fed 
by being successively gripped, pushed forward, clamped to 
hold in place, let go of by the gripper and, later, undamped, 
the grippers meanwhile being returned to their original posi- 
tion ready to repeat the operation ad libitum. Such a feed is 
often used for sheets of cardboard in cutting playing-cards, 
either singly or in gangs. It is especially useful for this pur- 
pose where great accuracy is required and where no finger- 





Fig. 417. 



Fig. 418. 





Fig. 419. Fig. 420. 

gauge arrangement can be used against the edge of the paper 
itself, on account of its inherent weakness. The same remarks 
will sometimes apply to certain thin and fragile metallic work. 

In Fig. 418 is shown a grip-feed, operated on the above- 
named step-by-step principle and arranged for cutting a gang 
of seven playing-cards at each stroke of the press upon which 
it is mounted, which in this case happens to be of the double- 
crank variety. 

In Fig. 419 is shown, mounted upon a small press, a feed- 



PRESS-FEEDING. 239 

attachment of the same sort, but operating upon only one 
card ai" a time. Such machines are, of course, applicable for 
metal work as well as paper and other soft materials. 

Carriage-feeding. 

In Fig. 420, attached to a punching-press, is shown another 
form of intermittent linear feed, such as is used for punching 
holes along the edge of boiler-sheets, and work of like char- 
acter. This is usually done one hole at a time, but sometimes 
with a gang of a few punches set in a row. The distinctive 
feature appearing in this device is a table-like carriage to 
which the sheet of material is clamped, and which is moved 
bodily in two directions, at right angles to each other. This 
movement can be automatic, and obviously may be made as 
accurate as that of a lathe-carriage. 

A positive feed of this sort is sometimes used for playing- 
cards, instead of the kind shown in Fig. 418. This is the best 
system, for such work must be cut very accurately, " register- 
ing " by the printing which is already upon the sheets. 
Otherwise, too much temptation might fall in the path of 
those gentlemen who like to read the face of a card by an 
irregular margin upon the back. 

In general, a carriage-feed may be made much more positive 
and uniform than can any of the others described. Per contra, 
the roller-feeds are the least so, and for accurate spacing must 
be supplemented by finger-gauge or " pintle " devices. For 
a specimen of the latter see Fig. 266, Chapter VI. 

Dial-feeding. 

Various automatic devices are in use for feeding partly 
made articles to dies whose functions are the performing of 
secondary or tertiary operations, etc. These are sometimes 
reciprocating, a sliding or swinging receptacle coming forward 
to receive the work and then carrying it back and holding it 



240 PRESS-WORKING OF METALS. 

between the dies during their operation upon it. Much 
oftener, however, these devices are rotary in their motion, 
the most common form being an intermittently revolving 
wheel which, with its appurtenances, is commonly known as 
a dial-feed. This is much used in re-drawing cartridges, as, 
for instance, where the " cups " made in the first operation 
are placed by hand into recesses in a horizontal dial-wheel 
revolving upon a vertical axis, the machine running contin- 
uously at a speed consistent with thus placing the articles 
manually. There is plenty of room at the front of this dial, 
which is several inches in diameter, for the operator to vary 
somewhat from an automaton and yet get a cup in every 
hole. Should one occasionally be missed, it of course does no 
harm. Each cup is brought in succession under the deepen- 
ing punch, the dial stopping for a sufficient length of time for 
it to be pushed down through the die and for the punch to 
be returned above the upper plane of the dial, which then 
revolves through another stage of its progress while the punch 
goes still further upward and returns part of the way down. 

In Figs. 42 1 and 422 are shown ordinary types of dial-feeds 
mounted respectively upon a double-action cam press and a 
re-drawing press. Fig. 423 shows a special combination of 
an intermittent dial-feed, together with a number of different 
kinds of dies treating the work successively and a roller-feed 
for introducing a different material (in this case paper) into 
the metallic work placed in the dial. 

It may be interesting to notice the three very different 
methods shown for driving the dials above referred to, the 
last-mentioned one being simply a " drunken worm," as it 
may be termed, meshing into a special gear, where the worm 
threads are arranged in a spiral position a part of the way 
around, and are nothing but simple collars, lying in normal 
planes throughout the remainder of the periphery. The 
second dial mentioned is driven by a device resembling the 



PRESS-FEED ING. 



241 



venerable stop-winder used on music-boxes, watches, etc, 

The dial first shown is operated 

by the well-known pawl and 

ratchet so often employed for 

intermittent motions. This latter 

is generally subject to the uncer- 






Fig. 421. Fig. 422. Fig. 423. 

tainties incident to a dependence upon springs, friction, and 
inertia, Sometimes, however, a locking device is provided. 

Friction-dials. 

In certain cases such work as has been mentioned is per- 
formed by what is known as a "friction-dial," whereon a 
number of cups, or such like, are stood up together in an 
irregular group alongside of each other, at the large end or 
opening of a curved wedge-shaped recess, whose walls are 
stationary and whose bottom is the flat, continuously-moving 
horizontal disk or dial. The question as to which of the 
pieces of work shall get in first is somewhat a matter of 
chance, as they are simply all hustled onward miscellaneously 
— on something the same principle as a crowd trying to enter 
a gate at a football game. The one who happens to be 
ahead is pushed into the gate first, which gate, in the case of 
the machine in question, is a definite opening leading to a 
space above the lower die. When it is pushed downward, 
sufficiently operated upon, and left beneath the die, then the 
next one is, by the same frictional action, pushed into its 
place. This process is adapted only to shallow articles with 
flat bottoms, as tall slim ones would be apt to upset and try 



242 PRESS-WORKING OF METALS. 

to enter the dies in a wrong position. Obviously, very broad 
thin objects, like buttons for instance, would also be unsuit- 
able, as they would have a tendency to slip over one another. 
They should therefore be approximately of the same height 
as width, and should be cylindrical rather than conical. 

In Fig. 424 is sho.wn a friction dial-feed which thus 
revolves continuously, carrying a group of pieces of work back 
in the massed condition described. As fast as they can get 
to their desired final position they are, of course, checked by 





Fig. 424. Fig. 425. 

a proper stop. The punch then pushes each one through the 
die beneath, and this gives room for the next one to take its 
place. 

Indexing. 

In Fig. 425 is shown a rotary "step-by-step," or inter- 
mittent, feed for punching notches or holes in armature-disks, 
and similar work. As mounted upon a small press it is some- 
times called an " indexer, " and sometimes a "notching 
press." The thin disc to be punched is clamped between two 
circular gripping-chucks, which are governed in their motion 
by the ratchet-dial at the top, containing the desired number 
of teeth. This is driven by a pawl operated from the press 
shaft. In some cases the dial is placed below the work. 

Sometimes the axis of an indexing-feed is placed horizon- 
tally or in an inclined position. This adapts it for cutting 
holes or notches, or groups of the same, in the sides of 
cylindrical or conical objects respectively. Lamp-burners and 
such like, are often perforated in this way. 



PRESS-FEEDING. 243 

GRAVITY-FEEDING. 

It is evident that with a horizontal press, long straight 
bars of metal might be stood up end-wise and fed into the 
dies by gravity — if governed by a proper finger-gauge or its 
equivalent. In practice this is not often done, a vertical 
position not being convenient for handling such bars. With 
an inclined press, however, this scheme might well be adopted 
oftener than it is. 

A common application of gravity for delivering work to dies 
is seen in the " tube-feed," in coining presses, where a pile of 
blanks, guided in a tube, descend of themselves as fast as 
the lower one is pushed automatically from under the rest. 
This device appears in Figs. 135 to 138, Chapter III. 

In certain cases an inclined trough, with the blanks edge 
to edge, is used as a gravity-feed. Indeed, small cups, or 
other regular objects of almost any kind may be thus fed, 
under favorable conditions. 

Many other curious feeds might be added to the ones 
above mentioned, but those given will answer as sufficient 
samples illustrating the general principles involved. 

Knockouts. 

In addition to the feeding devices proper which have been 
described, many of which feed the work in rather than out, 
there is a distinct class of ejecting press- or die-attachments 
known by the general name of " knockouts," or sometimes 
and if limited to the lower die, as" knockups." " Ejectors " 
would probably have been a better name, had fate so willed 
it — and had men more logical minds. 

Some of these devices have been described in former chap- 
ters as integral parts of the dies themselves. In such cases 
they are usually, . although not always, operated by springs, 
and may be situated either in the upper or lower die, or both. 



244 PRESS-WORKING OF METALS. 

In other cases, the " pads " that do the pushing out are set 
loosely in the dies and are operated by a special device, 
sometimes known as a portable knockout, which is attached 
to the press as temporarily a part thereof. Such attachments 
are often operated by springs, but in many cases are mechani- 
cally connected to some moving part of the press. In certain 
instances this connection is a mere attachment to the ram by 
rods or otherwise, so that the stem of the knockout will rise 
with it, either to the full extent of its stroke or with some 
" lost motion." In other cases the device is collected with a 
cam upon the main shaft, so as to move properly at a pre- 
determined time, independently of the ram. 

In Fig. 426, at CD, is shown a portable spring-knockout 
mounted beneath a pair of dies. The stem upon 
which the spring C slides is screwed in below. 
This spring is supported and regulated by the nuts 
D, and pushes up the flanged sleeve against a group 
of loose pins projecting below the die. These 
run up under the ejecting pad thereof, and slide 
upward when the downward pressure is relieved by 
Fig 426. the ascent of the ram. In some cases the knock- 
out stem is screwed into the bolster instead of the 
die, the push-pins extending down through the same. The 
construction of this device is almost identical with the spring- 
drawer shown in Fig. 364, page 202. 

A device similar in principle, but more compact, is some- 
times inserted in the ram, to give a downward thrust. At 
other times a slot running through the ram receives a station- 
ary beam attached to some part of the press frame. In other 
cases this beam becomes a lever, which changes the amount 
of the motion, the effect with either method being to drive 
downward a plate acting upon pins set in the upper die. 

An advantage of either of the last-named attachments is 
that when once applied to a press they will answer for any 




PRESS-FEEDING. 245 

number of suitable dies that may be interchangeable therein, 
without requiring the extra complication of a set of springs, 
etc., mounted in each individual die. 

The knocking-out of work is occasionally performed by an 
air-blast — as is also the pushing down home into a die of cer- 
tain small pieces which happen to be imperforated and which 
fit tight enough to serve as pistons. 

PUSHOUTS. 

Certain other ejecting devices, known sometimes as" push- 
outs," are closely akin to the knockouts just described. 
These are generally used for pushing pieces of work horizon- 
tally out through an opening in the back or side of the lower 
die, the punch having delivered it only so far down, on ac- 
count of there being an anvil-like matrix beneath to do em- 
bossing, or for some other analogous reason. The pushing 
member of the device is usually automatic, but is occasion- 
ally arranged to work by hand. 

Sometimes an air-blast is used to thus eject work sidewise. 
While mentioning such blasts, it may be said that they are 
more frequently used to eject " scale," or other dirt that has 
fallen from, or that has been scraped off, the metal. Espe- 
cially is this needed in working red-hot iron in forming dies. 

Feeding Speeds. 

In hand-feeding, expert operators learn to move the work 
synchronously with the press ram's motion, even at as high a 
speed in some cases as 240 times a minute, in such work as 
cutting small blanks from a strip of metal, etc. Usually, 
however, the speed is much slower, averaging perhaps 100 
strokes a minute for continuous running and fewer where the 
press is started each time with the clutch. With foot or 
hand presses, as a general rule, still less speed is attained. 

With automatic feeds of various kinds there is no definite 
limit in regard to speed. In general, it may be said that a 



246 PRESS-WORKING OF METALS. 

feeding device will run as fast as will the press in which it is 
mounted, the limitations in the case of both being due chiefly 
to the conditions of weight and inertia happening to be 
present. These conditions vary greatly, however, in indi- 
vidual cases. With gravity-feeds Dame Nature has of course 
exhibited her law of falling bodies and uttered her interdict, 
" Thus far shalt thou go and no further." 

Special Automatic Machines. 

In addition to the thousands, if not millions, of members 
composing the army of presses in active service, an army which 
is constantly mustering in new recruits for newly invented 
purposes, to an extent almost inconceivable to the past gen- 
eration, there are in use a number of modifications and ampli- 
fications of the power press proper. These may, in general, 
be denominated automatic metal-pressing machines, and they 
are of almost every conceivable design and degree of com- 
plexity. Many of them are hidden in their own lairs, never 
coming forth in the light of public gaze. Others, again, can 
be seen in metal factories of all sorts — in the domains of pin- 
making, hook- and eye- making, button-making, etc. 

Such machines usually turn out so enormous a product that 
they themselves are comparatively few in number. Being so 
few and so highly specialized, it naturally follows that they 
generally have not become regular articles of manufacture, 
but are worked out, one at a time, by a series of experiments. 
In many cases such a machine is but the perfected descendant 
of a line of ancestors, each of which has, in the course of its 
evolution, contributed new facts to the problem whose solu- 
tion is sought — only to die in its turn and be buried in a scrap- 
heap, giving place to some still further perfected child or grand- 
child. The final outcome of such heredity is, in certain cases, 
so marvelous a something that it seems to outvie human 
brains and fingers in the perfection and rapidity of its work. 



PKESS-FEEDING. 247 

Naturally, enormous sums of money have been spent upon 
developing machinery of this kind, and many wise and skillful 
mechanicians have been tempted to contract, for a fixed sum 
of money, to produce a perfected machine which proves, in 
the end, to cost perhaps ten times as much. Such money is 
generally well spent for somebody when the final result has 
been obtained, but is ill spared by the unlucky originator. 

Pertinent to these facts a piece of advice may be given to 
all inventors of special machines, which is to allow the owners 
thereof to furnish all the capital, while the designer (for pay) 
furnishes the knowledge and experience. If the latter in- 
dividual furnishes the money himself, as is too often the case, 
he will find in the end that he has not only furnished expe- 
rience, but has received a great deal that he did not expect. 

Any mechanical explanation of the machines referred 
to is here, of course, out of the question, as they are too 
infinite in variety. It may be said, in general, that many of 
them are modifications of power presses, having not only the 
normal vertical ram motion, perhaps duplicated above, below, 
and at the sides, but also various other rams, levers, etc., 
moving in other directions, as horizontally backward and for- 
ward, right and left, and diagonally. These motions are 
usually obtained by special cams, which move some given 
member to place, keeping it there as long as required and 
returning it home. Perhaps by this maneuver a cutting 
operation will be performed, leaving the cut blank in a cer- 
tain position with a " dwell " for a certain time, while some 
other member approaches and does something else to it, in the 
way, probably, of perforating it, bending or forming certain 
pirts of it, etc. Perhaps then some third member will ap- 
proach and do another thing, either in the way of operating 
upon it further or moving it to some other position. Finally, 
in most cases, a humble member known as a knockout or a 
pushout will act as a hall-porter and usher it forth beyond 



248 PRESS-WORKING OF METALS. 

the portals of the machine. In most instances a complex 
automatic organism of this sort has one main shaft which 
governs the motions of all the other members, and which 
revolves once for each complete cycle of " time." 

In certain special machines, as well as in some ordinary 
presses, the material used has to be brought to a given fixed 
temperature. This has been before treated of to a certain 
extent, but the apparatus for doing the heating, uniformly and 
at the proper time, must obviously be considered as pertain- 
ing to the automatic machines here under consideration. A 
case in point would be the interesting process (which, I think, 
somebody has patented) of automatically heating the metal by 
passing a current of electricity through it as it approaches the 
critical position where it must be worked. This is in princi- 
ple analogous to some of the other electrical processes per- 
taining to welding and forging which are so rapidly being 
worked out. It is difficult to foresee what the development 
of this electrical pressing may prove to be in future, but it 
is evidently only one of the many heretofore unsupposed uses 
to which electricity may be applied. 



MISCELLA NEO US. 249 



CHAPTER XIII. 
MISCELLANEOUS. 

Manifolding Work in Dies. 

It has been taken for granted, in describing various press- 
working operations in which the use of dies is involved, that 
but one thickness of metal was to be worked at a time, 
although in describing the drawing process reference was made 
to working two or three pieces at once. It is obviously pos- 
sible, however, to thus manifold work, as it may be termed, 
in various bending and forming operations, providing the same 
condition is admissible as in drawing conical pans inside of 
one another, viz., that the inner ones shall be smaller than the 
outer. In coining-work a duplication of pieces in the dies at 
one time is of course out of the question. In cutting and 
punching flat sheets or bars we obviously have the most 
favorable conditions for going through several thicknesses at 
once, as all the blanks thus cut would be practically of the 
same size. As a matter of fact, two or three thicknesses of 
thin metals, such as tin-plate, sheet-iron, etc., are often cut 
at a single stroke of the dies by being piled one upon another 
when fed. The writer has recently made some definite ex- 
periments as to how many layers it is possible to thus cut, 
and has succeeded in making as many as a dozen blanks at a 
time. 

It is evident that under such conditions the upper blank 
which touches the punch must act as the punch for the next 
one, and that for the one below it, and so forth. Thus the 
metal is being cut by a tool no harder than itself, with the 



250 PRESS-WORKING OF METALS. 

result that might be expected, a certain crushing and tearing 
around the edges which gives a very uncouth effect. The lower 
blanks and the upper" margins" are not only extremely 
rough where cut apart, but are somewhat bent up around the 
edge into a little conical flange, thus making the blanks 
slightly cup-shaped. This bad effect of course increases with 
the number worked at once, getting worse and worse on the 
blanks as they are removed farther from the punch, and on 
the margins as they are farther from the top of the lower die. 

In practice two or three layers of metal are probably about 
as many as it is worth while to attempt to cut at one time, 
although if smoothness and flatness are of no consequence 
more might be worked in some cases. It may be asked why 
several layers of thin metal will not punch as well as with the 
same total thickness aggregated into a thicker plate. It is 
true that in the latter case the pushing down of all the lower 
parts of the blank have to be done by portions of its own 
materia' above, but in the former case, of a number of sep- 
arate plates, we have a laminated structure in which each layer 
can slide somewhat over the adjacent one, as the fibres are 
bent out of their normal plane. 

In working paper it has been found that very many more 
layers can be cut at a time than in the case of metal. 

Paper-working. 

The greater portion of the ensuing remarks upon paper- 
cutting are extracts from an article published by me in The 
American Machinist, giving the results of certain experiments 
which, though not exactly germane to the subject of this 
book, may be of interest as showing some of the doings of an 
* ordinary press and dies originally made for metal working. 

" The object of the experiments referred to was: 1st, to 
ascertain the best angle of cutting edges for ordinary male and 
female dies, when used in cutting paper and pasteboard; 2d, 



MISCELLANEO US. 



251 



to see how many thicknesses could be successfully cut under 
various conditions; 3d, to note the pressure required. For 
this purpose a pair of round dies, cutting to a diameter of ity 
inches was used, a section and top view of the same being 
shown in Fig. 427. 

' In the first batch of experiments the punch and die 
were both made perfectly flat with the angles A and B each 
90 degrees, the edges being sharp and the punch fitting the 
die with a close but easy sliding fit, say, not over one five- 
thousandth of an inch loose. 

" The second condition of the dies was as in Fig. 428, 
with the lower die still flat, and the punch beveled out so as 





c3BL 




Fig. 428. 



Fig. 429. 




r 



j' 



Fig. 427. Fig. 430. Fig. 431. 

to make the angle of cutting edge at A 60 degrees, which 
angle seemed to be (after a few trials with other inclinations) 
the most appropriate for the purpose. 

" Under condition third, the punch was flat and the die 
beveled to an angle of 60 degrees, as in Fig. 429. 

" Under condition fourth, both punch and die had their 
edges beveled at A and B, to angles of 60 degrees, as in Fig. 

43°- 

" With dies in condition first, from one to five sheets of 
manilla paper, .012" thick, could be cut at a time when piled 
together, the cutting being reasonably smooth. When ten 



252 PRESS-WORKING OF METALS. 

were cut at a time some of them were rough and ragged, and 
with twenty at once the roughness was too great for any ordi- 
nary purposes, both with the " blanks " and " margins." 
With pasteboard .057" thick (one sheet at a time), the cut- 
ting was very good, and with two sheets at a time, slightly 
ragged. With pasteboard of a softer quality, .105" thick 
(one sheet at a time) the cutting was fairly good only, being 
slightly ragged. 

" In all these cases, as might be expected, both blanks 
and margins remained flat. 

' Under condition second, much smoother edges were pro- 
duced when cutting a number of sheets at a time, on account 
of the sharp angle of the punch — work almost smooth being 
produced ten at a time, and fairly good twenty at a time, the 
pasteboard also showing better results than before. As might 
be expected, however, the paper blanks were bent upward into 
the concave recess of the punch, when cutting more than 
about five or six at a time, to an extent calculated to render 
them useless for ordinary purposes. This was especially the 
case when cutting twenty at once, a number of the upper- 
most blanks in the pile being very much wrinkled, and the 
pasteboard blanks showing a raised bead near the edge caused 
by the radial compression. As might also be expected in 
this case, the margins remained fiat, without injurious 
wrinkles. 

" Under condition third, with the punch flat, and the die 
having an edge whose section was an acute angle, the ex- 
pected again happened, the paper blanks being flat and smooth 
all the way through, and the margins being permanently bent 
and wrinkled when cut in piles of more than five or six sheets 
at a time — so much so as to render them unfit for ordinary 
use. With twenty sheets at a time the lowermost margins 
were embossed out to a cup-shape where they were forced 
over the conical portion of the lower die to about T 3 F inch 



MIS CELL A NEO US. 253 

deep, while the central ones of the pile had a depressed flange 
something on the counterbore order, the uppermost ones being 
nearly flat, but slightly wrinkled. In the case of the paste- 
board something of the same effect occurred, but not to so 
great an extent. 

Under condition fourth, the cutting was still smoother 
than in any of the other cases, with less of the ragged -edge 
effect, even twenty sheets at once being cut in fairly good 
shape. As might be supposed, however, the evils cited in the 
last two paragraphs, viz., cupping and wrinkling of the blanks, 
in the one case, and of the margins in the other, were here 
united as twin evils, although the distortions did not seem to 
be quite as great in either case as with the other dies." 

In regard to the actual and relative pressures required for 
paper-punching under the various conditions named, no accu- 
rate records were made, but the figures varied from 3000 to 
6000 pounds per square inch of section cut. The lower press- 
ures were attained with the sharpest angles, as in Fig. 430. 

" In Fig. 431 are shown the tools for a more usual method 
of cutting paper, pasteboard, cloth, leather, etc., than by the 
use of the male and female dies just under consideration. 
These work upon the chiseling principle, and consist of a 
hollow cutter with its angle A at the cutting edge about 20 
degrees, and its depth from I inch to \\ inch, together 
with a matrix or anvil, C, upon which the cutting is done — 
usually a sheet of copper, soft-brass, lead or pasteboard, the 
latter being probably the most frequently used. This rests 
upon an iron plate, D, set upon the bed of the press. In some 
cases, however, a wooden anvil, preferably with the end grain 
toward the cutters, is used in place of the plate C. The cutter 
is usually placed by hand upon the pile of paper sheets, which 
are slid under the ram-driven platen of the press. This of 
course descends upon the top of the cutter, and pushes it down 
exactly in contact with C. The blanks are generally removed 



254 PRESS-WORKING OF METALS. 

by hand, although in some cases the cutter is reversed, and 
so mounted upon a lower die-plate (something after the fashion 
of Fig. 429) that the blanks may fall through of themselves as 
they are pushed down by the following blanks in succeeding 
operations. In still other cases they are pushed upward by an 
automatic kncckup, worked by springs or otherwise. In either 
of these last-named cases a spring-stripper is sometimes fur- 
nished for pushing the pile of margins off from the outside of 
the cutter, instead of removing them by hand." 

In some recent experiments I found that a cutter of this 
kind would cut smoothly some 300 thicknesses of ordinary 
printing-paper at a time, the whole pile being about 1 inch 
thick. The pressure per square inch of section cut was, 
roughly speaking, some 2000 to 3000 pounds, the larger 
diameters naturally taking the least force per inch, on account 
of less stretching of the margins, proportionately, being re- 
quired. 

The purposes for which paper is cut into definite shapes 
are of course very numerous. Among them are playing- and 
photograph-cards, labels, valentines, and so-called paper dolls 
of every imaginable complexion and every degree of beauty 
and ugliness. 

The forming and drawing processes are also practiced upon 
paper and other soft substances — usually when in a dampened 
condition, with the dies kept hot upon a bolster having a 
steam-coil inside. Similarly, an operation analogous to coin- 
ing is performed upon thick pasteboard and sometimes on 
leather. 

In nearly all these cases the presses are the same as those 
used for metal-working. 

Hammer-blows. 

In compaiing the efficacy and general desirability of a 
quick hammer-like blow, as given by a drop press, with the 



MIS CELL A NEO US. 255 

slower pressure given by a crank-driven ram or the ram of a 
hydraulic press, there are various circumstances to be taken 
into account. In general, where hard work is to be done 
through a very short distance, as in smashing out wrinkles or 
embossing a shallow design in sheet-metal, etc., a given press- 
ure can be obtained for less money with a drop press than 
with its more expensive rivals. This is because of its sim- 
plicity as an agent for storing power, there being, as with other 
members of the hammer family, no kinetic mechanism through 
which heavy pressures must be conveyed from a power-storing 
fly-wheel. The lifting of a weight by any rough device that 
is strong enough for its work, with no particular accuracy of 
motion, and the subsequent letting go of it, so that gravity 
may do the rest, gives us an ideal simplicity, the only accu- 
rate mechanism necessary being a pair of columns to <nride 
the hammer-like ram so that it will fall in its proper place. 

The varying circumstances above referred to are too 
numerous to be scheduled here. Among them are the tem- 
perature of the metal, its thickness, its capacity for quick flow 
among its particles, etc. One important point in favor of 
a slow, positive, action is that the metal is affected uni- 
formly, or nearly so, all the way through, while with a quick 
hammer-blow it is, on account of the inertia bf its own par- 
ticles, affected mostly upon the outside. This causes varia- 
tions of density, and in heavy forgings an openness of internal 
structure not conducive to the greatest strength. Witness 
the " piping," or central cavities, sometimes occurring in 
large shafts which do not get pressure enough to squeeze 
them together. 

In the case of small articles of hot metal the chilling of 
the surfaces by the action of dies which are massive in propor- 
tion to the work is a serious objection to the use of a slow- 
moving ram. It is, however, more important to attain a quick 
opening of the dies than a quick closing together, as a com- 



256 PRESS-WORKING OF METALS. 

paratively slow closing has the advantage above mentioned of 
allowing the met^il to flow properly, while every moment that 
they remain closed upon the work gives a clear loss of heat. 
This is especially the case where a number of successive blows 
are to be given, and for such action the drop press is not a 
suitable machine, as the lifter does not act immediately, or 
with great initial rapidity. For such work a trip-hammer 
has been found a very useful tool, although the accuracy 
of its motion is not all that can be desired. 

A heavy, geared, toggle press might seem to be a good 
machine for the hot squeezing of small articles weighing but a 
few ounces. This is not the case, however, as the terminal 
closing and initial opening are so slow with a toggle-motion 
that the work is as cold as the dies before it is fully squeezed. 
A non-geared, rather fast-moving machine is evidently desir- 
able, and it is quite possible to construct a big, special, press 
whose kinetic arrangement shall give the ram a moderately 
quick closure and a more rapid opening, — at the same time 
retaining some of the advantages of a toggle-motion in the 
way of avoiding friction under heavy pressure. The general 
characteristics of such a machine were well described by a 
friend of mine with the analogies, " As strong as an elephant, 
anr 1 as quick as a cat." 

Effective Pressure in Drop Presses. 

A mysterious efficiency is sometimes claimed for a drop 
press blow, as having some wonderful inherent property not 
attainable by an ordinary ram pressure. There is, however, 
nothing in such a blow but what can be resolved into the sim- 
ple elements of force measured in pounds and motion measured 
in feet or inches. In estimating the actual pressure attained 
it is not even necessary to go into the mathematics of the 
laws of gravitation, as a simple calculation which will resolve 



MISCELLANEOUS. 257 

the action of the hammer into foot-pounds is all that is 
required. 

If, for instance, a one-hundred-pound ram is lifted ten feet 
there must be necessarily be (disregarding for the time being 
the friction of the guiding columns as of little account) 
iooo foot-pounds of stored energy, which is bound to be 
given out during the time that the ram is being stopped by 
its action upon the work. If this action takes place during 
the last one foot of its fall, then the average pressure through 
that foot will be iooo lbs., dying away to nothing as it reaches 
the bottom of its stroke. If the distance through which work 
is done is one inch, then the average pressure will be 12,000 
lbs. If, as is more likely in sheet-metal work, the actual 
pressure is required through, say, one tenth inch, then the 
average pressure will be 120,000 lbs. In other words, the 
total foot-pounds divided by the distance in feet through 
which the ram is doing effective work will give the average 
number of pounds pressure exerted upon the same. In prac- 
tice some 10 per cent maybe deducted from these figures for 
friction and motion wasted in heat, etc., — the amount varying 
with circumstances. 

This, however, is assuming that the anvil or bed of the 
press is of ample weight, so that much of the force of the 
blow will not be wasted in moving it and its supports. The 
latter should not be of springy timber-work, as of old, but of 
solid masonry, extending down to bed-rock where feasible. 

As compared with a drop press a slow-running mechanical 
or hydraulic press is better for cold metals, which usually will 
flow better to a new form if treated slowly than when called 
upon for a violent and sudden disarrangement of their particles. 
The same thing may be said in regard to hot metals of such 
large bulk that there is little danger of the chilling of the sur- 
faces by contact with the dies. The truth of this statement 
may be verified by citing the fact that within a few years past 



2 c 8 PRESS-WORKING OF METALS. 

many of the great steel-works in this country and Europe are 
substituting hydraulic presses of enormous power (10,000 tons 
pressure being considered nothing remarkable) for the big 
steam-hammers formerly used. The action thus obtained 
upon great ingots of white-hot steel used for forging cannon, 
steamer-shafts, and such work, is found to be both quicker 
and better. 

Testing Pressures. 

The pressure required for doing any sort of die work, from 
cutting to coining, is often a desirable thing to know, but is 
generally with press-users a sadly unknown quantity. The 
most accurate method of obtaining this knowledge is to use a 
regular testing-machine, arranged for compression, preferably 
equipped for giving an automatic record of the pressures at 
each instant of the closing of the dies, which are temporarily 
mounted therein. Such tests are usually not available in a 
press-working shop, but a rough test used in my own practice 
for ascertaining what a press ram would do has been to place 
between two flat, hardened, plates, one mounted upon the bed 
and the other upon the ram, certain pieces of bar-iron, of the 
same size and quality as certain other ones which had been 
previously tested for compression in a regular laboratory. 
The value of this of course depends upon the uniformity of 
the metal, but for approximate work it has been found suf- 
ficient to use y square American iron — annealed and cut up 
in short pieces, l" , 2", 3", 4", and 5" long, etc. 

These pieces, when laid on their sides and smashed to about 
T V thick, so as to widen to T V' wide, represent somewhere 
near one ton (of 2000 pounds) pressure for each -£$" in length. 
1 " would therefore represent 20 tons; 2", 40 tons; 4", 80 tons, 
etc. For lighter pressures, smaller sections of iron could be 
used and the system could be carried out with various other 
modifications. Doubtless copper would be more uniform and 



MIS CELL A NEO US. 259 

give better results than iron, but might not be as cheap and 
convenient to get hold of. At a future time I hope to make 
public more accurate records in regard to the behavior of 
different qualities of iron, and to give a more definite rule for 
reading results. 

I also hope to further develop a certain device to which I 
have given considerable study, but have not yet perfected. 
This is a portable, recording, compression-testing machine, in 
the form of a bolster which can be placed upon the bed of any 
ordinary press. To its upper surface will be secured any die 
in which work is to be tested. By allowing sufficient resist- 
ance between the dies the capacity of the press can of course 
be tested also. The difficulties to be overcome are chiefly 
due to the small available space at command and to the 
great range of pressures requiring to be weighed with the 
same instrument. 

Electric Driving. 

Until recently power presses have been driven with belts 
from countershafts or from line-shafting, but it is now 
becoming the fashion, to some small extent, to equip each 
press with an individual electric motor. It is to be hoped 
that this fashion will increase and mutliply, as the advantages 
of such driving are too numerous to be mentioned in detail 
here. Obviously, the convenience of standing a machine any- 
where, in any position, and connecting to it by a pair of wires 
dropping from the ceiling, or, preferably, coming up through 
the floor, are manifest, especially as the speed can be accu- 
rately controlled, and the power is used only at the exact time, 
and to the exact amount needed, without waste from shaft- 
friction, belt-resistance, etc. Furthermore, the advantages of 
clear overhead shop-room, with its incidental increase of light, 
cleanliness, and safety, are almost beyond computation, when 
compared with the methods of our grandfathers and our 



26o PRESS-WORKING OF METALS. 

fathers — and of ourselves, in those ancient times some four or 
five years ago, before we knew about these things. 

The above remarks do not refer to an electric or magnetic 
press proper, as mentioned in an earlier chapter. Such direct 
driving of a press ram by electro-magnets has not as yet been 
developed very far, except in the analogous case of rock-drills, 
and perhaps occasionally an electric hammer. 

Power Required for Presses. 

The horse-power required to drive a press is usually quite 
small in comparison with that absorbed by many other ma- 
chines of about the same general size. This is because the 
speeds are comparatively slow, and the down-strokes, which 
do the hard work, are intermittent. Again, we have in lit- 
erature few, if any, definite data based upon dynamometrical 
tests of actual work. 

An approximate estimate of the power that a mediumly 
tight driving-belt of a power press can supply may be made 
by the old rule of multiplying the diameter of the driven 
pulley (which oftentimes is the fly-wheel also) by belt-width, 
both in inches, and by revolutions per minute, dividing the 
product by 3000, the quotient from which will be the horse- 
power. Such result may be discounted quite freely by guess 
— say from 25 to 75 per cent. This is to allow for the hal- 
cyon moments of waste time, so to speak, between the down 
strokes of the ram, when the belt is doing almost nothing, 
except, indeed, at certain times to restore the depreciated 
speed of the heavy fly-wheel that is (or ought to be) present 
in every such machine in order that a part of the power may 
be freely stored therein for each critical time of need. The 
discount referred to will be greater in instances where the main 
shaft is stopped after each stroke by its clutch, because in such 
case the ram will be actually at work during a less proportion 



MISCELLANEOUS. 26l 

of its total time than with a continuously running shaft. The 
observer must judge in each particular case as to how much 
of the time actual work is being done in overcoming friction 
or otherwise. Of course much better than all this would be 
the use of a good recording dynamometer (could a suitable 
one be obtained), from whose records the power used could 
be averaged. 

An excellent substitute for the above-mentioned instru- 
ment, in cases of electric driving, is the presence of an ampere- 
meter or watt-meter in the circuit. The voltage being 
known, a little mental translation will enable the observer to 
read the greatly varying horse-power at each individual 
instant. 

Future Development. 

The wonderful evolution of some of the various proc- 
esses involved in the art which is the subject of this treatise 
has before been referred to. It is a well-known fact that our 
commercial metals are all the time being developed into a 
more suitable quality and form for being acted upon by dies, 
and that hundreds of inventors are busily at work contriving 
new devices for the household, the ship, the farm, the road, 
and every other department of human activity. Moreover, the 
tendency is constantly to cheapen and unify various parts of 
these devices, striking them out in dies from malleable material 
rather than producing them by the older processes of hand- 
forging and casting. It is impossible to predict how far this 
line of evolution may go in the future, but at present the 
prospects seem to point toward a more and more thorough 
and frequent use of the processes in question as the years go 
on. 

Unquestionably very many articles of common and neces- 
sary use, which serve to add to the pleasure, convenience, 
and consequent happiness of mankind, and womankind, too, 
have been increased in number and improved in quality by the 



262 PRESS-WORKING OF METALS. 

facility with which they can be produced in presses and dies. 
Truly, if the man is to be commended who can " make two 
blades of grass grow where grew one before," how much can 
be said of those men whose toiling brains and hands are pro- 
viding the means by which not. two only, but two thousand, 
useful and beautiful things can be furnished to the waiting 
multitude for a price at which but one could be obtained by 
their fathers and their grandfathers ! Shall not the Recording 
Angel say of each of these busy workers, like Abou Ben 
Adhem, he " loves his fellow-men "? 



INDEX. 



A 

PAGE 

Accuracy in dies 06 

Aluminum 95 

for cooking utensils . 192 

coins and medals.. 228 

American gauges 99, 103 

Railway Mast. Mech. Asso 112 

Soc. of Mechanical Engineers 112 

Anatomy of presses , 20 

Annealing metals , 120 

for drawing. , 192 

Anvil principle 38 

and hammer 16 

Armature disks I3g 

Artistic design in presses 36 

metal-working 13 

Art of metal-work, origin and history 11, 14 

Assembling work in dies 162 

by curling 172, 173, 174 

Attaching dies 77 

Automatic machines 246 



B 

Bar metals r f. 

Co 

Belts, horse-power of 260 

Bending processes 154 

in dies je^ 

Bevel of cutting-edges jac 

Blank dimensions 2 oa 

formulae 20 6, 207 

Blank-holders jog 

vee 2IO 

multiple 219 

Blanks, a museum 01 236, i^" 1 

263 



264 INDEX, 

PAGB 

Blanks and margins 131 

Blank sizes, mensurative finding 206 

gravitative finding 205 

tentative finding 205 

Blows, hammer. 254 

Body-wrinkles 194 

systematized 195 

Bolsters for presses 76 

Brass 95 

Brick presses 230 

Britannia 95 

Broaching 218 

Brown & Sharpe gauge no 

Bubble-blowing . 166 

Burs in shearing and punching 126 

Buying metals 97 

presses 35 



Cartridge re-drawing 240 

Carlyle, Thomas 98 

Carriage-feeding 239 

Casting punches in place 164 

under pressure.. 12 

Chart of gauges, Wheeler's. 100 

Cheapening utensils by drawing processes „ 222 

Chiseling « 123 

cutters for paper, angle of. .0 253 

dies • 124 

Chucks, for dies 81 

Clamping pads in shearing 146 

dies 78,85 

Classification of presses 20 

Clearance in cutting dies 143 

Clutches 39 

Coining coins ■ 225 

presses 67, 68 

flow in 227 

presses 231 

press, quick-running 23 r 

pressures • 231 

processes 223 

speeds 231 

Coins of aluminum 228 

reeding of = .. , =, 226 



INDEX. 265 

PAGE 

Coins, ejecting 225 

fins upon 227 

milling of '• • 226 

Cold flow of solids 188 

Columnar presses » 24 

Combination cutting. 138 

Commercial metals 95. 0. 97 

Composite press frames 24 

Compressing plastic substances 229 

Conical drawing 19° 

Copper • 95 

Corks rising through pitch 389 

Cranks and cams 64 

Curling and seaming processes 167 

assembling by 172, 173. J 74 

by rolling • - 2I ° 

dies 168 

in horning presses 60, 61 

inwardly • 1 7 l 

irregular T 73 

or wiring presses J ° 2 

outwardly. x ^7 

pressures 1 ° 2 

principles of J 75 

processes • I °7 

speeds I ° 2 

straight work J 79 

tapered work l6 9- 170 

Cutting die qualifications • T 4 2 

dies T 3° 

-drawing-embossing T 99 

edge bevels J 45 

-forming-embossing ■■- 159,160 

presses «■ 50, 50 

pressures t I ^° 

processes I2 3 

speeds r 47 

with gang-dies J 3 8 



D 

Dangers of press-feeding 2 34 

Decimal-gauge notch sizes proposed 177 

Deepening process 2I 4 

Deep punching J 33 



266 INDEX. 

PAG* 

Depth of drawing 192 

Design in machinery, artistic principles. 192 

Diagrams of press motions 29, 30, 31 

Dial and roller feed combined 240 

Dial-feeding , 239 

Die chucks 81 

clamps 78, 48 

gauges 177 

hardness 143 

interchangeability 76 

knockouts 161 

lubrication 92 

nomenclature 93 

pressures in cutting ,. 148 

sexes ...... $ 93 

sharpen ings 142 

specimens, pictures of .87, 88, 89, qg 

speeds in cutting 147 

work manifolding 249 

Dies, accuracy and durability 86 

attaching to pieces 77 

classified by functions 75 

comparative cost of 87 

composite construction of 88 

cutting-forming-embossing. 159, 160 

definitions and evolutions 73 

for cutting and punching 131 

for cutting successively 131, 149 

for curling or wiring 168 

for double curling 171 

for shearing 124, 125 

for assembling work 162 

for bending 154 

for chiseling 124 

jjior embossing 158 

testing fit of 159 

for forming 155, 156 

functions 93 

height of 91 

Dip or shear ..126, 127 

Double-action presses 62, 63, 65 

-crank presses. 52, 53 

curling dies 171 

Drawing, annealing for 172 

conditions of dies for 198 

conical 190 



INDEX. 267 



PAGE 



Drawing, defined x 85 

depth of i9 2 

historically 184 

mammoth work 222 

mechanics of 186 

presses 62, 63, 65, 212 

pressures 210 

process analogies 1S9 

processes • • • • 184 

prophetically 222 

speed 210 

of 19°. 217 

springing of tools in 210 

spring 203 

with cutting and embossing • • . 199 

Drawn-work, lubrication of . 199 

manifolded ..-,. 197 

proportions.. 196 

specimens of 201 

temperature of • - 199 

Drifting or re-punching 136 

tools 136 

Driving by electricity 259 

Drop forging • ■ 223 

fins on • ■ • 224 

trimming of 224 

presses . .26, 47, 48 

press pressure, effective 225 

Drop-presses, stored energy •- 257 

Duplication in die- work 73 

by press-work • 13 

Durability in dies • ■ 86 



Ejecting coins 225 

Ejectors 243 

Electric driving • 259 

Embossing in dies • 157 

presses 54> 55 

with cutting and drawing.. 199 

speeds 161 

pressures « 161 

Energy, stored • • • • 257 

English presses 43 



268 INDEX. 



PAGE 



European gauges I02 > io 5 

Evans, Mr 67 



Feeding attachments 233 

by grip devices 238 

by gravity 243 

by hand * 234 

by rollers 236 

by reels 237 

by revolving dials. 239 

by sliding carriages 239 

presses 233 

speeds . 234, 245 

Feeders • 233 

Feeds 233 

indexing. 242 

Fins in coining 227 

on drop forgings 224 

Fiddle principle • 38 

Flanges, internal. 157 

Flange wrinkles. 195 

Flatness of work after punching 132 

F low of glaciers • 188 

of solids, elastic. ° 188 

of solids. .0 13, 161 

of metals. 188 

in coining. 227 

of solids, not elastic • . 1S8 

Fluid punches 165 

Foolishness in wire-gauges 100 

Foot-presses 46, 57 

Foreign presses 43 

Forging processes • ■> 12 

by slow pressure 257 

■rming in dies • • 155. 166 

pressures 161 

speeds • 161 

Frame design of presses 22 

Franklin Institute..... °. 188 

Friction-dials • 241 

Fruit-can tops . - 142 

Functions of presses 34 

of dies 75 

Future development of press-work 261 



INDEX. 269 

G 

PAGE 

Gang cutting or punching 138 

Gas-hammers 71 

Gauge, a proposed new 112, 113 

decimal i I2 , 113 

nomenclature 304 

numbers, qualifications of 116 

modifications „ 108 

micrometer ug, 120, 121 

Gauges for metals » g8 

Gauging in dies 147 

German presses , 43 

Glass-blowing !66 

Glacial flow !S8 

Gold -jc 

Graphic analysis in drawing 1S7 

Gravity-feeding 243 

Grip-feeding 238 

Grosjean, Mr 184 



H 

Hammer-blows 254 

Hammering machines. 70, 71 

Hand feeding 233 

presses 44, 45 

Hardness of dies 143 

Hold-downs and strippers 145 

Hoopes & Townsend 134 

Horning or side seaming 170 

and curling presses 60, 61 

Horse-power of belts 2 bo 

Hot forging, rapidity of 2g . 

Hydraulic presses gq -g 

I 

Indexing feeds 242 

Inclined presses t .- co ci 

Internal forming Ie ._ 

Inventing wire-gauges q g 

Inverted, re-drawing 2l6 

Involuntary processes T 5 2 

Inward curling > p< I7 

International gauges ri » 

Irregular curling I7 

Ir ° n ••• ».'.".".'" 95 



2/0 INDEX. 

K 

PAGE 

Kinetic construction of presses 28 

Knockouts 243 

portable 244 

in dies 161 



L 

Lead 95 

pipe squirting 230 

Lever presses 46, 47 

Limit in depth of drawing 192 

Literature of presses 42 

Lock-seams 1S0 

Lower and upper dies * 93 

Lubrication of dies and materials 92 

M 

Machines, automatic 246 

Machine-tool analogies 37 

Mammoth drawing processes 222 

Manifolding in paper-cutting 254 

work in dies 249 

Marchand, Mr 184 

Margins and blanks 131 

Materials and measurements 95 

worked in presses 34 

Measurement of materials 95 

Mechanics of drawing ■ 186 

Medals • 226 

Metal buying 97 

Micrometer gauges 119, 120, 121 

Milling coins 226 

Mints 67 

Motions of presses ■ 20 

Multiple drawing 197 

Museum of blanks I3 6 . *37 

presses 4 2 

Mutilation by press-feeding 235 

N 

Name-guessing for presses 34 

Neck-reducing • 22T 



INDEX. 271 

PAGE 

Neidringhaus, Mr jg 4 

Nickel q;. 

Nomenclature of dies no 



O 
Ou t'vard curling xtn 

P 

Paper cutting manifolded 254 

working 250 

working pressures 253 

Patenting old processes 217 

Pendulum presses a ft 47 

.Perforated metal jog 

Pictorial collection of presses 43 

Piping in forgings , , 255 

Plane he ts for coins. 225 

Plastic substances, compression and molding of 229 

Platinum or 

Power applications to presses 33 

press problems 37 

required for presses 260 

Position of presses 20 

Portable knockouts 244 

Press bolsters 76 

buyers, points for „ 35 

classification and anatomy 20 

classification by functions 33 

by frame design 22 

by kinetic construction 28 

by materials worked 9,4 

by method of support 27 

by motions 20 

by position 20 

construction, primal principles 17 

definitions 16 

feeding, definitions of 233 

literature 42 

nomenclature 18 

work, future development of 261 

working, principles of 12 

Fresses, coining , . .67, o3 

cutting 50,51 



2/2 INDEX. 

PAG* 

Presses, drawing .62, 63, 65, 212 

double-action 62, 63, 64 

double-crank .52, 53 

drop. 48, 49 

embossing 54. 56 

foot 46, 57 

for brick 230 

for curling or wiring 182 

for cutting. . . . 153 

for forming and embossing 166 

for re-drawing 221 

for seaming , 182 

for horning , 183 

for soap 230 

hand 44, 45 

hydraulic 69, 70 

inclined 47, 50, 51 

lever 46, 47 

pendulum 46, 47 

power for 260 

punching 54. 5° 

qualifications 16 

re drawing 64, 66 

reducing 64, 66 

safety devices 1 234, 235 

screw 44, 45 

toggle 62, 63, 65, 67, 68 

twinned 52, 53 

wiring 60, 61 

Pressure for coining 231 

for drawing 210 

for cutting dies 148 

for paper-working. 253 

in drop presses, effective 251 

in forming and embossing „ 161 

with loose punches 135 

Primeval methods i, 14 

Principles of curling 175 

Proportions for drawn-work 196 

Prussian system of drawing 184 

Punches 93 

and shears 57.-58. 

fluid , 165 

of soft metal 164 

Punching 129 

presses 54, 56 

pressure reduced , . . 135 



INDEX, 2/3 

PAGB 

Punching tapering holes o 134 

Punchings or wads 131 

Pushouts ,. . . . 245 



9 

Quick-running coining-presses 231 

R 

Rams of presses. „ „ ig, 

heights from beds gr 

cross-sections. 24, 25 

Rapidity in hot forging 255 

Re-drawing presses 64, 66, 221 

pressures 221 

processes 214 

speeds 221 

upside down 216 

Reducing necks 221 

presses 64, 66 

processes..... 214 

Reeding coins f 226 

Reel-feeding 237 

Re-punching or drifting 136 

Rim-covers 220 

forming 220 

Riveting. 229 

Roller and dial feed combined 240 

curling 210 

feeding • 236 

spinning = 210 

Rotary operations 15 



s 

Safety devices for presses „ 235 

Screw-presses 44, 45 

Seams, special i8r 

Seaming or horning presses 183 

pressures 182 

processes 167 

speeds '. 182 

Sexes of dies gj 

Shapes of bar metals g-j 



274 INDEX. 

PAGE 

Sharpening dies by hammering. . . 143 

Shear-blades 84 

Shear or dip 126, 127 

Sheared surfaces, imperfect 135 

Shearing as affected by dies 150 

dies. 124, 125 

presses 27 

strength of various metals 149 

Shears and punches 57, 58 

squaring 47, 48, 52, 53 

Sheet-metal gauged by weight. , . . . 108 

Sheet-metals 96 

Side-seaming or horning 179 

Silver. 95 

Soap-presses 230 

Soft punches. 164 

Special automatic machines 246 

machinery 246 

machines, inventors of 247 

seams 181 

Specimen drawn -work .... 20 r 

Speed in forming and embossing. 161 

Speed of drawing. 190, 210 

Speeds for cutting-dies 147 

for seaming 182 

in coining 231 

for curling 182 

for re-drawing '. 221 

in drawing 210 

Spinning by rolling 210 

Spring-drawing 203 

Springing of work after bending 154 

of tools in drawing 210 

Sprue-cutting 125 

Squaring shears 47, 48, 52, 53 

Squirting of soft metals 230 

Stamping process 184 

Steam-hammers 71 

Steel 95 

Stones sinking through pitch 189 

Stored energy in drop-presses 257 

Straight curling 179 

Strength of metals, shearing 149 

of materials in drawing 193 

in drawing comparative 198 

Strippers and hold-downs 145 

Strou velle Bros 184 



INDEX. 275 

PAGE 

Sub-presses 40 

Successive cutting 139 

dies 139, 141 

gang-cutting 140, 141 

Suicidal press tendencies 39 

Supporting presses, methods of 27 



T 

Tapering holes, punched 134 

Temperature of material 248 

Tensile strength in drawing r g3 

Testing die sharpness 134 

fit of embossing dies „ I eg 

pressures 258 

Thickness of tin-plate „ IO y 

Throats of presses a j8 

Tin-plate gj 

thickness I0 y 

Toggle-presses 62, 63, 65, 67, 68 

Topography of machinery ig 

Trimming drop-forgings 224 

edges 209 

Trip-hammer work 255 

Tubal Cain and disciples n 

Tube feeds 243 

squirting 230 

Twin presses 52 53 

Tyndall, Prof , X 8g 



u 

Upper and lower dies 03 



V 

Vee blank-holders... 



W 



219 



Warping in forming and embossing...., 162 

Weighing-bolsters „ 25o 

Wet-paper test. „ j-. 

Wheeler, Dr. S. S., gauge charts by TOO 



2^6 INDEX. 

PAGE 

Whitworth, Sir Joseph 12, 106 

William Sellers & Co o 135 

Wire 96 

Wire-drawing sizes 109 

Wire-gauges 98 

foolishness of „ . . . . 98 

function of 98 

qualifications of 99 

standards for 99 

tables of 103, 105 

Wiring presses 60, 61 

processes 167 

Wrinkles, body 194 

flange 195 

Z 
Zinc . . . . 95 



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* Dyer's Handbook of Light Artillery 1 21110, 3 00 

Eissler's Modern High Explosives 8vo, 4 00 

* Fiebeger's Text-book on Field Fortification. Small 8vo, 2 00 

Hamilton's The Gunner's Catechism i8mo, 1 00 

* Hoff's Elementary Naval Tactics 8vo, 1 50 

Ingalls's Handbook of Problems in Direct Fire 8vo, 4 00 

* Ballistic Tables 8vo, 1 50 

* Lyons's Treatise on Electromagnetic Phenomena. Vols. I. and II. 8vo, each, 6 00 

* Mahan's Permanent Fortifications. (Mercur.) 8vo, half morocco, 7 50 

Manual for Courts-martial i6mo morocco, 1 50 

* Mercur's Attack of Fortified Places nmo, 2 00 

* Elements of the Art of War 8vo, 4 00 

Metcalf's Cost of Manufactures — And the Administration of Workshops, Public 

and Private 8vo, 5 00 

* Ordnance and Gunnery nmo, 5 00 

Murray's Infantry Drill Regulations i8mo, paper, 10 

* Phelps's Practical Marine Surveying 8vo, 2 50 

Powell's Army Officer's Examiner nmo, 4 00 

Sharpe's Art of Subsisting Armies in War i8mo, morccco, 1 50 

2 



* Walke's Lectures on Explosives 8vo, 4 00 

* Wheeler's Siege Operations and Military Mining '. .8vo, 2 00 

Winthrop's Abridgment of Military Law nmo, 2 50 

Woodhull's Notes on Military Hygiene i6mo, 1 50 

Young's Simple Elements of Navigation i6mo, morocco, 1 00 

Second Edition, Enlarged and Revised i6mo, morocco, 2 co 



ASSAYING. 

Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe. 

nmo, morocco, } 1 50 

Furman's Manual of Practical Assaying 8vo, 3 00 

Miller's Manual of Assaying nmo, 1 00 

O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 00 

Ricketts and Miller's Notes on Assaying 8vo, 3 00 

Ulke's Modern Electrolytic Copper Refining 8vo, 3 00 

Wilson's Cyanide Processes nmo, 1 50 

Chlorination Process nmo, 1 50 



ASTRONOMY. 

Comstock's Field Astronomy for Engineers 8vo, 2 50 

Craig's Azimuth 4to, 3 50 

Doolittle's Treatise on Practical Astronomy 8vo, 4 00 

Gore's Elements of Geodesy 8vo, 2 50 

Hayford's Text-book of Geodetic Astronomy 8vo, 3 00 

Merriman's Elements of Precise Surveying and Geodesy 8vo, 2 50 

* Michie and Harlow's Practical Astronomy 8vo, 3 00 

* White's Elements of Theoretical and Descriptive Astronomy nmo, 2 00 



BOTANY. 

Davenport's Statistical Methods, with Special Reference to Biological Variation. 

i6mo, morocco, 1 25 

Thome and Bennett's Structural and Physiological Botany i6mo, 2 25 

Westermaier's Compendium of General Botany. (Schneider.) 8vo, 2 00 



CHEMISTRY. 

Adriance's Laboratory Calculations and Specific Gravity Tables nmo, 1 25 

Allen's Tables for Iron Analysis 8vo, 3 00 

Arnold's Compendium of Chemistry. (Mandel.) (In preparation.) 

Austen's Notes for Chemical Students nmo, 1 50 

Bernadou's Smokeless Powder. — Nitro-cellulose, and Theory of the Cellulose 

Molecule nmo, 2 50 

Bolton's Quantitative Analysis 8vo, 1 50 

* Browning's Introduction to the Rarer Elements 8vo, 1 50 

Brush and Penfield's Manual of Determinative Mineralogy 8vo, 4 00 

Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.) . . . ,8vo, 3 00 

Cohn's Indicators and Test-papers nmo, 2 00 

Tests and Reagents 8vo, 3 00 

Copeland's Manual of Bacteriology. (In preparation.) 

Craft's Short Course in Qualitative Chemical Analysis. (Schaeffer.). . . . nmo, 2 00 

Drechsel's Chemical Reactions. (Merrill.) nmo, 1 25 

Duhem's Thermodynamics and Chemistry. (Burgess.) (Shortly.) 

Eissler's Modern High Explosives 8vo, 4 00 



Effront's Enzymes and their Applications. (Prescott.) 8vo, 3 00 

Erdmann's Introduction to Chemical Preparations. (Dunlap.) nmo, 1 25 

Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe. 

nmo, morocco, 1 50 

Fowler's Sewage Works Analyses nmo, 2 00 

Fresenius's Manual of Qualitative Chemical Analysis. (Wells.) 8vo, 5 00 

Manual of Qualitative Chemical Analysis. Parti. Descriptive. (Wells.) 

8vo, 3 00 
System of Instruction in Quantitative Chemical Analysis. (Cohn.) 
2 vols. (Shortly.) 

Fuertes's Water and Public Health nmo, 1 50 

Furman's Manual of Practical Assaying 8vo, 3 00 

Gill's Gas and Fuel Analysis for Engineers nmo, 1 25 

Grotenfelt's Principles of Modern Dairy Practice. ( Woll.) nmo, 2 00 

Hammarsten's Text-book of Physiological Chemistry. (Mandel.) 8vo, 4 00 

Helm's Principles of Mathematical Chemistry. (Morgan.) nmo. 1 50 

Hinds's Inorganic Chemistry 8vo, 3 00 

* Laboratory Manual for Students nmo, 75 

Holleman's Text-book of Inorganic Chemistry. (Cooper.) 8vo, 2 50 

Text-book of Organic Chemistry. (Walker and Mott.) 8vo, 2 50 

Hopkins's Oil-chemists' Handbook 8vo, 3 00 

Keep's Cast Iron 8vo, 2 50 

Ladd's Manual of Quantitative Chemical Analysis nmo. 1 00 

Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 00 

Lassar-Cohn's Practical Urinary Analysis. (Lorenz.) nmo, 1 co 

Leach's The Inspection and Analysis of Food with Special Reference to State 

Control. (In preparation.) 

Lob's Electrolysis and Electrosynthesis of Organic Compounds. (Lorenz.) nmo, 1 00 

Mandel's Handbook for Bio-chemical Laboratory nmo, 1 50 

Mason's Water-supply. (Considered Principally from a Sanitary Standpoint.) 

3d Edition, Rewritten 8vo, 4 00 

Examination of Water. (Chemical and Bacteriological.) nmo, 1 25 

Meyer's Determination of Radicles in Carbon Compounds. (Tingle.). . nmo, 1 00 

Miller's Manual of Assaying nmo, 1 00 

Mixter's Elementary Text-book of Chemistry nmo, 1 50 

Morgan's Outline of Theory of Solution and its Results nmo, 1 00 

Elements of Physical Chemistry nmo, 2 00 

Nichols's Water-supply. (Considered mainly from a Chemical and Sanitary 

Standpoint, 1883.) 8vo, 2 50 

O'Brine's Laboratory Guide in Chemical Analysis 8vo, 2 00 

O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 00 

Ost and Kolbeck's Text-book of Chemical Technology. (Lorenz — Bozart.) 
(In preparation.) 

* Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 

8vo, paper, 50 
Pictet's The Alkaloids and their Chemical Constitution. (Biddle.) (In 
preparation.) 

Pinner's Introduction to Organic Chemistry. (Austen.) nmo, 1 50 

Poole's Calorific Power of Fuels 8vo, 3 00 

* Reisig's Guide to Piece-dyeing 8vo, 25 00 

Richards and Woodman's Air .Water, and Food from a Sanitary Standpoint . 8vo, 2 00 

Richards's Cost of Living as Modified by Sanitary Science nmo, 1 00 

Cost of Food, a Study in Dietaries nmo, 1 00 

* Richards and Williams's The Dietary Computer 8vo, 1 50 

Ricketts and Russell's Skeleton Notes upon Inorganic Chemistry. (Part I. — 

Non-metallic Elements.) 8vo, morocco, 75 

Ricketts and Miller's Notes on Assaying. . 8vo, 3 00 

Rideal's Sewage and the Bacterial Purification of Sewage 8vo, 3 50 

4 



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Ruddiman's Incompatibilities in Prescriptions 8vo 2 00 

Schimpf's Text-book of Volumetric Analysis... 12 mo' 2 so 

Spencer's Handbook for Chemists of Beet-sugar Houses.'. .'.'.'.'16010', morocco', 3 00 
Handbook for Sugar Manufacturers and their Chemists . . i6mo, morocco, 2 00 
Stockbndge's Rocks and Soils 8vo 

* Tillman's Elementary Lessons in Heat gvo' 

* Descriptive General Chemistry 8vo ' 

Treadwell's Qualitative Analysis. (Hall.) '.'.'. 8vo 3 oc 

Turneaure and Russell's Public Water-supplies '.'. 8v0 ' - 00 

Van Deventer's Physical Chemistry for Beginners. (Boltwood.)'. I2 mo' 1 ko 

■ Walke's Lectures on Explosives 8vo' 4 o 

Wells's Laboratory Guide in Qualitative Chemical Analysis. . . . . . .' .' . 8vo ' 1 50 

Short Course in Inorganic Qualitative Chemical Analysis for Engineering 

Students 

Whipple's Microscopy of Drinking-water. . "^vo' \ so 

Wiedemann's Sugar Analysis '.'.'.'.'.'.'.'.'.'.Small 8vo.' 2 50 

Wilson's Cyanide Processes 



Chlorination Process . 



. i2mo, 1 50 
i2mo, 1 50 



Wulling's Elementary Course in Inorganic Pharmaceutical and Medical Chem 
istry 

I2fflO, 2 00 

CIVIL ENGINEERING. 

BRIDGES AND ROOFS. HYDRAULICS. MATERIALS OF ENGINEERING 
RAILWAY ENGINEERING. 

Baker's Engineers* Surveying Instruments I2mo , 00 

f* iX y S , G A raphical Computing Table Paper.VgVx 24'i inches' 25 

** Burr s Ancient and Modem Engineering and the Isthmian Canal. (Postage, 

27 cents additional.) 8vo ' t . 

Comstock's Field Astronomy for Engineers .. ... 8vo ' 2 50 

Davis's Elevation and Stadia Tables " 8vo' 1 00 

Elliott's Engineering for Land Drainage. . . i 2 mo' 1 50 

Practical Farm Drainage .'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.' '. 12m o, 1 00 

Folwell s Sewerage. (Designing and Maintenance.) Svo 3 00 

Freitag's Architectural Engineering. 2d Edition, Rewritten. . 8vo' 3=50 

French and Ives's Stereotomy 8vo ' 2 * 

Goodhue's Municipal Improvements i2mo ' 1 

Goodrich's Economic Disposal of Towns' Refuse 8vo' 3 so 

Gore's Elements of Geodesy 8v ' 

Hayford's Text-book of Geodetic Astronomy 8vo' 3 00 

Howe's Retaining Walls for Earth V-,™' T -,.. 

T , , i2mo, 1 25 

Johnson s Theory and Practice of Surveying Small 8vo, 4 00 

Statics by Algebraic and Graphic Methods 8vo' 2 00 

Kiersted's Sewage Disposal " I2mo ' t 

Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.')' i 2 mo' 2 00 

Mahan's Treatise on Civil Engineering. (1873 ) (Wood.) 8vo' 5 00 

* Descriptive Geometry 8vo Q 

Merriman's Elements of Precise Surveying and Geodesy. ...... . . . . . . . . . 8vo,' 2 50 

Elements of Sanitary Engineering 8vo ' 2 0Q 

Merriman and Brooks's Handbook for Surveyors.'.'.'.'.'.'.'.'..'.' .'.'i6mo', morocco ' 2 00 

Nugent's Plane Surveying 

Ogden's Sewer Design. . . 

° i2mo, 2 00 

Patton s Treatise on Civil Engineering Svo, half leather, 7 50 

Reed s Topographical Drawing and Sketching J 4to> 5 00 

Rideal's.'Sewage and the Bacterial Purification of Sewage 8vo', 3 50 

Siebert and Biggin's Modern Stone-cutting and Masonry .8vo,' 1 50 

Smith's Manual of Topographical Drawing. (McMillan.) g vr> ' 2 50 

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25 


4 


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3 


50 



-ondericker's Graphic Statics, with Applications to Trusses, Beams, and 
Arches. (Shortly.) 

* Trautwine's Civil Engineer's Pocket-book i6mo, morocco, 

Wait's Engineering and Architectural Jurisprudence 8vo, 

Sheep, 
Law of Operations Preliminary to Construction in Engineering and Archi- 
tecture 8vo. 

Sheep, 

Law of Contracts 8vo, 

Warren's Stereotomy — Problems in Stone-cutting 8vo : 

Webb's Problems in the U c e and Adjustment of Engineering Instruments. 

i6mo, morocco, 

* Wheeler's Elementary Course of Civil Engineering 8vo, 

Wilson's Topographic Surveying 8vo, 



BRIDGES AND ROOFS. 

Boiler's Practical Treatise on the Construction of Iron Highway Bridges. .8vo, 2 00 

* Thames River Bridge 4to, paper, 5 00 

Burr's Course on the Stresses in Bridges and Roof Trusses, Arched Ribs, and 

Suspension Bridges 8vo, 3 50 

Du Bois's Mechanics of Engineering. Vol. II Small 4to, 10 00 

Foster's Treatise on Wooden Trestle Bridges 4to, 5 00 

Fowler's Coffer-dam Process for Piers 8vo, 2 50 

Greene's Roof Trusses 8vo, 1 25 

Bridge Trusses 8vo, 2 50 

Arches in Wood, Iron, and Stone 8vo, 2 50 

Howe's Treatise on Arches 8vo 4 00 

Design of Simple Roof-trusses in Wood and Steel 8vo, 2 00 

Johnson, Bryan, and Turneaure's Theory and Practice in the Designing of 

Modern Framed Structures Small 4to, 10 00 

Merriman and Jacoby's Text-book on Roofs and Bridges: 

Part I. — Stresses in Simple Trusses 8vo, 2 50 

Part II. — Graphic Statics 8vo, 2 50 

Part III. — Bridge Design. 4th Edition, Rewritten 8vo, 2 50 

Part IV. — Higher Structures 8vo, 2 50 

Morison's Memphis Bridge 4to, ro 00 

Waddell's De Pontibus, a Pocket-book for Bridge Engineers. . . i6mo, morocco, 3 00 

Specifications for Steel Bridges nmo, 1 25 

Wood's Treatise on the Theory of the Construction of Bridges and Roofs.8vo. 2 00 
Wright's Designing of Draw-spans: 

Part I. — Plate-girder Draws 8vo, 2 50 

Part II. — Riveted-truss and Pin-connected Long-span Draws 8vo, 2 50 

Two parts in one volume 8vo, 3 50 



HYDRAULICS. 

Bazin's Experiments upon the Contraction of the Liquid Vein Issuing from an 

Orifice. (Trautwirie.) 8vcr, 2 00 

Bovey's Treatise on Hydraulics 8vo, 5 00 

Church's Mechanics of Engineering 8vo, 6 00 

Diagrams of Mean Velocity of Water in Open Channels paper, 1 50 

Coffin's Graphical Solution of Hydraulic Problems i6mo, morocco, 2 50 

Flather's Dynamometers, and the Measurement of Power i2mo, 3 00 

Folwell's Water-supply Engineering 8vo, 4 00 

Frizell's Water-power 8vo, 5 00 



Fuertes's Water and Public Health i2mo, i 50 

Water-filtration Works nmo, 2 50 

Ganguillet and Kutter's General Formula for the Uniform Flow of Water in 

Rivers and Other Channels. (Hering and Trautwine.) 8vo, 4 00 

Hazen's Filtration of Public Water-supply 8vo, 3 00 

Hazlehurst's Towers and Tanks for Water-works 8vo, 2 50 

Herschel's 115 Experiments on the Carrying Capacity of Large, Riveted, Metal 

Conduits 8vo, 2 00 

Mason's Water-supply. (Considered Principally from a Sanitary Stand- 
point.) 3d Editisn, Rewritten 8vo, 4 00 

Merriman's Treatise on Hydraulics, gth Edition, Rewritten 8vo, 5 00 

* Michie's Elements of Analytical Mechanics 8vo, 4 00 

Schuyler's Reservoirs for Irrigation, Water-power, and Domestic Water- 
supply Large 8vo, 5 00 

** Thomas and Watt's Improvement of Riyers. (Post., 44 c. additional), 4to, 6 00 

Turneaure and Russell's Public Water-supplies 8vo. 5 00 

Wegmann's Design and Construction of Dams 4to, 5 00 

P* Water-supply of the City of New York from 1658 to 1895 410, 10 00 

Weisbach's Hydraulics and Hydraulic Motors. (Du Bois.) 8vo, 5 00 

Wilson's Manual of Irrigation Engineering Small 8vo, 4 00 

Wolff's Windmill as a Prime Mover 8vo, 3 00 

Wood's Turbines 8vo, 2 50 

Elements of Analytical Mechanics 8vo, 3 00 



MATERIALS OF [ENGINEERING. 

Baker's Treatise on Masonry Construction 8vo, 5 00 

Roads and Pavements 8vo, 5 00 

Black's United States Public Works Oblong 4to, 5 00 

Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 

Burr's Elasticity and Resistance of the Materials of Engineering. 6th Edi- 
tion, Rewritten 8vo, 7 50 

Byrne's Highway Construction 8vo, 5 00 

Inspection of the Materials and Workmanship Employed in Construction. 

i6mo, 3 00 

Church's Mechanics of Engineering 8vo, 6 00 

Du Bois's Mechanics of Engineering. Vol. I Small 4to, 7 50 

Johnson's Materials of Construction Large 8vo, 6 00 

Keep's Cast Iron 8vo, 2 50 

Lanza's Applied Mechanics 8vo, 7 50 

Martens's Handbook on Testing Materials. (Henning.) 2 vols 8vo, 7 50 

Merrill's Stones for Building and Decoration 8vo, 5 00 

Merriman's Text-book on the Mechanics of Materials 8vo, 4 00 

Strength of Materials i2mo, 1 00 

Metcalf' s Steel. A Manual for Steel-users i2mo, 2 00 

Patton's Practical Treatise on Foundations 8vo, 5 00 

Rockwell's Roads and Pavements in France i2mo, 1 25 

Smith's Wire : Its Use and Manufacture Small 4to, 3 00 

Materials of Machines i2mo, 1 00 

Snow's Principal Species of Wood 8vo, 3 50 

Spalding's Hydraulic Cement i2mo, 2 00 

Text-book on Roads and Pavements i2mo, 2 00 

Thurston's Materials of Engineering. 3 Parts 8vo, 8 00 

Part I. — Non-metallic Materials of Engineering and Metallurgy 8vo, 2 00 

Part II. — Iron and Steel 8vo, 3 50 

Part III. — A Treatise on Brasses, Bronzes, and Other Alloys and their- 

Constituents 8vo, 2 so 

7 



Thurston's Text-book of the Materials oflConstruction] 8vo, 5 00 

Tillson's Street Pavements and Paving Materials 8vo, 4 00 

Waddell's De Pontibus. (A Pocket-book for Bridge Engineers.)- ■ i6mo, mor., 3 00 

Specifications for Steel Bridges i2mo, 1 25 

Wood's Treatise on the Resistance of Materials, and'an Appendix on the Pres- 
ervation of Timber 8vo, 2 00 

Elements of Analytical Mechanics 8vo, 3 00 



RAILWAY ENGINEERING. 

Andrews's Handbook for Street Railway Engineers. 3X5 inches, morocco, 1 25 

Berg's Buildings and Structures of American Railroads 4to, 5 00 

Brooks's Handbook of Street Railroad Location i6mo, morocco, 1 50 

Butts's Civil Engineer's Field-book i6mo, morocco, 2 50 

Crandall's Transition Curve i6mo, morocco, 1 50 

Railway and Other Earthwork Tables 8vo, 1 50 

Dawson's "Engineering" and Electric Traction Pocket-book. i6mo, morocco, 4 00 

Dredge's History of the Pennsylvania Railroad: (1879) Paper, 5 00 

* Drinker's Tunneling, Explosive Compounds, and Rock Drills, 4to, half mor., 25 00 

Fisher's Table of Cubic Yards Cardboard, 25 

Godwin's Railroad Engineers' Field-book and Explorers' Guide i6mo, mor., 2 50 

Howard's Transition Curve Field-book i6mo, morocco, 1 50 

Hudson's Tables for Calculating the Cubic Contents of Excavations and Em- 
bankments Svo? 1 00 

Molitor and Beard's Manual for Resident Engineers 161110, 1 00 

Nagle's Field Manual for Railroad Engineers i6mo, morocco. 3 00 

Philbrick's Field Manual for Engineers i6mo, morocco, 3 00 

Pratt and Alden's Street-railway Road-bed 8vo, 2 00 

Searles's Field Engineering i6mo, morocco, 3 00 

Railroad Spiral i6mo, morocco, 1 50 

Taylor's Prismoidal Formulae and Earthwork 8vo, 1 50 

* Trautwine's Method of Calculating the Cubic Contents of Excavations and 

Embankments by the Aid of Diagrams 8vo, 2 00 

* The Field Practice of Laying Out Circular Curves for Railroads. 

i2mo, morocco, 2 50 

* Cross-section Sheet Paper, 25 

Webb's Railroad Construction. 2d Edition, Rewritten i6mo. morocco, 5 00 

Wellington's Economic Theory of the Location of Railways Small 8vo, 5 00 



DRAWING. 

Barr's Kinematics of Machinery 8vo, 2 50 

* Bartlett's Mechanical Drawing 8vo, 3 00 

Coolidge's Manual of Drawing 8vo, paper, 1 00 

Durley's Kinematics of Machines 8vo, 4 00 

Hill's Text-book on Shades and Shadows, and Perspective 8vo,1 2 00 

Jones's Machine Design: 

Part I.— Kinematics of Machinery 8vo, 1 50 

Part II. — Form, Strength, and Proportions of Parts 8vo, 3 00 

MacCord's Elements of Descriptive Geometry 8vo, 3 00 

Kinematics; or, Practical Mechanism 8vo, 5 00 

Mechanical Drawing 4to, 4 00 

Velocity Diagrams 8vo, 1 50 

* Mahan's Descriptive Geometry and Stone-cutting Svo, 1 50 

Industrial Drawing. (Thompson.) 8vo, 3 50 

Reed's Topographical Drawing and Sketching 4to, 5 00 



Reid's Course in Mechanical Drawing 8vo, 2 00 

Text-book of Mechanical Drawing and Elementary Machine Design. ,8vo, 3 00 

Robinson's Principles of Mechanism 8vo, 3 00 

Smith's Manual of Topographical Drawing. (McMillan.) 8vo, 2 50 

Warren's Elements of Plane and Solid Free-hand Geometrical Drawing . . i2mo, 1 00 

Drafting Instruments and Operations i2mo, 1 25 

Manual of Elementary Projection Drawing i2mo, 1 5° 

Manual of Elementary Broblems in the Linear Perspective of Form and 

Shadow i2mo, 1 00 

Plane Problems in Elementary Geometry i2mo, 1 25 

Primary Geometry i2mo, 75 

Elements of Descriptive Geometry, Shadows, and Perspective 8vo, 3 50 

General Problems of Shades and Shadows 8vo, 3 °° 

Elements of Machine Construction and Drawing 8vo, 7 5° 

Problems. Theorems, and Examples in Descriptive Geometrv 8vo, 2 50 

Weisbach's Kinematics and the Power of Transmission. (Hermann and 

Klein.) 8vo, 5 00 

Whelpley's Practical Instruction in the Art of Letter Engraving i2mo, 2 00 

Wilson's Topographic Surveying . , 8vo, 3 50 

Free-hand Perspective ° vo » 2 So 

Free-hand Lettering. (In preparation.) 

Woolf's Elementary Course in Descriptive Geometry Large 8vo, 3 00 



ELECTRICITY AND PHYSICS. 

Anthony and Brackett's Text-book of Physics. (Magie.) Small 8vo, 3 °° 

Anthony's Lecture-notes on the Theory of Electrical Measurements. .... i2mo, 1 00 

Benjamin's History of Electricity 8vo, 3 00 

Voltaic Cell 8vo, 3 00 

Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.). .8vo, 3 o° 

Crehore and Squier's Polarizing Photo-chronograph 8vo , 3 00 

Dawson's "Engineering" and Electric Traction Pocket-book. . iomo, morocco, 4 00 

Flather's Dvnamometers, and the Measurement of Power i2mo, 3 00 

Gilbert's De Magnete. (Mottelay.) 8vo, 2 50 

Holman's Precision of Measurements 8vo, 2 00 

Telescopic Mirror-scale Method, Adjustments, and Tests Large tivo, 75 

Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 00 

Le Chatelier's High-temperature Measurements. (Boudouard — Burgess.)i2mo, 3 00 

Lob's Electrolysis and Electrosynthesis of Organic Compounds. (Lorenz.) i2mo, 1 00 

* Lyons's Treatise on Electromagnetic Phenomena. Vols. I. and II. 8vo, each, 6 00 

* Michie. Elements of Wave Motion Relating to Sound and Light 8vo, 4 00 

Niaudet's Elementary Treatise on Electric Batteries. (FishDacK. ) i2mo, 2 50 

* Parshall and Hobart's Electric Generators Small 4to. half morocco, 10 00 

* Rosenberg's Electrical Engineering. (Haldane Gee — Kinzbrunner.). . . .8vo, 1 50 
Ryan, Norris, and Hoxie's Electrical Machinery. (In preparation- ■ 

Thurston's Stationary Steam-engines 8vo, 2 50 

* Tillman's Elementary Lessons in Heat 8vo, 1 50 

Tory and Pitcher's Manual of Laboratory Physics Small 8vo, 2 00 



LAW. 

* Davis's Elements of Law 8vo, 2 50 

* Treatise on the Military Law of United States 8vo, 7 00 

* - Sheep, 7 50 
Manual for Courts-martial i6mo, morocco, 1 50 

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Wait's Engineering and Architectural Jurisprudence. . . . 8vo, 

Sheep, 
Law of Operations Preliminary to Construction in Engineering and Archi- 
tecture 8vo, 

Sheep, 

Law of Contracts '. 8vo, 

Winthrop's Abridgment of Military Law i2mo, 



MANUFACTURES. 

Bernadou's Smokeless Powder — Nitro-cellulose and Theory of the Cellulose 

Molecule i2mo, 2 50 

Bolland's Iron Founder nmo, 2 50 

" The Iron Founder," Supplement i2mo, 2 50 

Encyclopedia of Founding and Dictionary of Foundry Terms Used in the 

Practice of Moulding nmo, 3 00 

Eissler's Modern High Explosives 8vo, 4 00 

Effront's Enzymes and their Applications. (Prescott.) 8vo, 3 00 

Fitzgerald's Boston Machinist i8mo, 1 00 

Ford's Boiler Making for Boiler Makers i8mo, 1 00 

Hopkins's Oil-chemists' Handbook 8vo, 3 00 

Keep's Cast Iron 8vo, 2 50 

Leach's The Inspection and Analysis ofJFood with Special Reference to State 

Control. (In preparation.) 

Metcalf's Steel. A Manual for Steel-users i2mo, 2 00 

Metcalfe's Cost of Manufactures — And the Administration of Workshops, 

Public and Private 8vo, 5 00 

Meyer's Modern Locomotive Construction 4to, 10 00 

* Reisig's Guide to Piece-dyeing 8vo, 25 00 

Smith's Press-working of Metals 8vo, 3 00 

Wire : Its Use and Manufacture Small 4to, 3 00 

Spalding's Hydraulic Cement nmo, 2 00 

Spencer's Handbook for Chemists of Beet-sugar Houses i6mo, morocco, 3 00 

Handbook for Sugar Manufacturers and their Chemists.. . 1 6mo, morocco, 2 00 
Thurston's Manual of Steam-boilers, their Designs, Construction and Opera- 
tion 8vo, s 00 

Ulke's Modern Electrolytic Copper Refining 8vo, 3 00 

* Walke's Lectures on Explosives 8vo, 4 00 

West's American Foundry Practice nmo, 2 50 

Moulder's Text-book nmo, 2 50 

Wiechmann's Sugar Analysis Small 8vo, 2 50 

Wolff's Windmill as a Prime Mover 8vo, 3 00 

Woodbury's Fire Protection of Mills 8vo, 2 50 



MATHEMATICS. 

Baker's Elliptic Functions 8vo, 1 50 

* Bass's Elements of Differential Calculus . m nmo, 4 00 

Briggs's Elements of Plane Analytic Geometry nmo, 1 00 

Chapman's Elementary Course in Theory of Equations nmo, 1 50 

Compton's Manual of Logarithmic Computations nmo, 1 50 

Davis's Introduction to the Logic of Algebra 8vo, 1 50 

* Dickson's College Algebra Large nmo, 1 50 

* Introduction to the Theory of Algebraic Equations Large nmo, 1 25 

Halsted's Elements of Geometry 8vo, 1 75 

Elementary Synthetic Geometry 8vo, 1 50 

'10 



* Johnson's Three-place Logarithmic Tables: Vest-pocket size paper, 15 

iod copies for 5 00 

* Mounted on heavy cardboard, 8 X 10 inches, 25 

10 copies for 2 00 

Elementary Treatise on the Integral Calculus Small 8vo, 1 50 

Curve Tracing in Cartesian Co-ordinates i2mo, 1 00 

Treatise on Ordinary and Partial Differential Equations Small 8vo, 3 50 

Theory of Errors and the Method of Least Squares i2mo, 1 50 

* Theoretical Mechanics i2mo, 3 00 

Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.) i2mo, 2 00 

* Ludlow and Bass. Elements of Trigonometry and Logarithmic and Other 

Tables 8vo, 3 00 

Trigonometry and Tables published separately Each, 2 00 

Maurer's Technical Mechanics. (In preparation.) 

Merriman and Woodward's Higher Mathematics 8vo, 5 00 

Merriman's Method of Least Squares 8vo, 2 00 

Rice and Johnson's Elementary Treatise on the Differential Calculus. Sm., 8vo, 3 00 

Differential and Integral Calculus. 2 vols, in one Small 8vo, 2 50 

Wood's Elements of Co-ordinate Geometry 8vo, 2 00 

Trigonometry: Analytical, Plane, and Spherical i2mo, 1 00 

MECHANICAL ENGINEERING. 
MATERIALS OF ENGINEERING, STEAM-ENGINES AND BOILERS. 

Baldwin's Steam Heating for Buildings i2mo, 

Barr's Kinematics of Machinery 8vo, 

* Bartlett's Mechanical Drawing 8vo, 

Benjamin's Wrinkles and Recipes i2mo, 

Carpenter's Experimental Engineering 8vo, 

Heating and Ventilating Buildings 8vo, 

Clerk's Gas and Oil Engine Small 8vo, 

Coolidge's Manual of Drawing 8vo, paper, 

Cromwell's Treatise on Toothed Gearing i2mo, 

Treatise on Belts and Pulleys i2mo, 

Durley's Kinematics of Machines 8vo, 

Flather's Dynamometers and the Measurement of Power nmo, 

Rope Driving nmo, 

Gill's Gas and Fuel Analysis for Engineers i2mo, 

Hall's Car Lubrication i2mo, 

Hutton's The Gas Engine. (In preparation.) 
Jones's Machine Design: 

Part I. — Kinematics of Machinery 8vo, 

Part II. — Form, Strength, and Proportions of Parts 8vo, 

Kent's Mechanical Engineer's Pocket-book i6mo, morocco, 

Kerr's Power and Power Transmission 8vo, 

MacCord's Kinematics; or, Practical Mechanism 8vo, 

Mechanical Drawing 4to, 

Velocity Diagrams ■ 8vo , 

Mahan's Industrial Drawing. (Thompson.) 8vo, 

Poole's Calorific Power of Fuels 8vo, 

Reid's Course in Mechanical Drawing 8vo, 

Text-book of Mechanical Drawing and Elementary Machine Design. .8vo, 

Richards's Compressed Air i2mo, 

Robinson's Principles of Mechanism 8vo, 

Smith's Press-working of Metals 8vo, 

Thurston's Treatise on Friction and Lost Work in Machinery and Mill 
Work 8vo, 

Animal as a Machine and Prime Motor, and the Laws of Energetics . nmo, 

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Warren's Elements of Machine Construction and Drawing 8vo, 7 50 

Weisbach's Kinematics and the Power of Transmission. Herr.nann — 

Klein.) 8vo, 5 00 

Machinery of Transmission and Governors. (Herrmann — Klein.). ,8vo, 5 00 

Hydraulics and Hydraulic Motors. (Du Bois.) 8vo, 5 00 

Wolff's Windmill as a Prime Mover 8vo, 3 00 

Wood's Turbines 8vo, 2 50 

MATERIALS OF ENGINEERING. 

Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 

Burr's Elasticity and Resistance of the Materials of Engineering. 6th Edition, 

Reset 8vo, 7 50 

Church's Mechanics of Engineering 8vo, 6 00 

Johnson's Materials of Construction Large 8vo, 6 00 

Keep's Cast Iron 8vo . 250 

Lanza's Applied Mechanics 8vo, 7 50 

Martens's Handbook on Testing Materials. (Henning.) 8vo, 7 50 

Merriman's Text-book on the Mechanics of Materials 8vo, 4 00 

Strength of Materials nmo, 1 00 

Metcalf's Steel. A Manual for Steel-users nmo 2 00 

Smith's Wire: Its Use and Manufacture Small 4to, 3 00 

Materials of Machines nmo, 1 00 

Thurston's Materials of Engineering 3 vols , Svo, 8 00 

Part II. — Iron and Steel 8vo, 3 50 

Part IH. — A Treatise on Brasses, Bronzes, and Other Alloys and their 

Constituents 8vo, 2 50 

Text-book of the Materials of Construction 8vo 5 00 

Wood's Treatise on the Resistance of Materials and an Appendix on the 

Preservation of Timber 8vo, 2 00 

Elements of Analytical Mechanics 8vo, 3 00 



STEAM-ENGINES AND BOILERS. 

Carnot's Reflections on the Motive Power of Heat. (Thurston.) nmo, 1 50 

Dawson's "Engineering" and Electric Traction Pocket-book. . T6mo, mor., 4 00 

Ford's Boiler Making for Boiler Makers i8mo, 1 00 

Goss's Locomotive Sparks 8vo, 2 00 

Hemenway's Indicator Practice and Steam-engine Economy nmo, 2 00 

Hutton's Mechanical Engineering of Power Plants 8vo, 5 00 

Heat and Heat-engines 8vo, 5 00 

Kent's Steam-boiler Economy 8vo, 4 00 

Kneass's Practice and Theory of the Injector 8vo, 1 50 

MacCord's Slide-valves 8vo, 2 00 

Meyer's Modern Locomotive Construction 4to, 10 00 

Peabody's Manual of the Steam-engine Indicator nmo, 1 50 

Tables of the Properties of Saturated Steam and Other Vapors 8vo, 1 00 

Thermodynamics- of the Steam-engine and Other Heat-engines 8vo, 5 00 

Valve-gears for Steam-engines 8vo,. 2 50 

Peabody and Miller's Steam-boilers 8vo, 4 00 

Pray's Twenty Years with the Indicator Large 8vo, 2 50 

Pupln's Thermodynamics of Reversible Cycles in Gases and Saturated Vapors. 

(Osterberg.) nmo, 1 25 

Reagan's Locomotives : Simple, Compound, and Electric nmo, 2 50 

Rontgen's Principles of Thermodynamics. (Du Bois.) 8vo, 5 00 

Sinclair's Locomotive Engine Running and Management nmo, 2 00 

Smart's Handbook of Engineering Laboratory Practice nmo, 2 50 

Snow's Steam-boiler Practice 8vo, 3 00 

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Spangler's Valve-gears 8vo, 2~so 

Notes on Thermodynamics i2mo, 1 00 

Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo, 3 00 

Thurston's Handy Tables 8vo, 1 50 

Manual of the Steam-engine . . r 2 vols. 8vo, 10 00 

Part I. — History, Structuce, and Theory 8vo, 6 00 

Part II. — Design, Construction, and Operation 8vo, 6 00 

Handbook of Engine and Boiler Trials, and the Use of the Indicator and 

the Prony Brake 8vo, 5 00 

Stationary Steam-engines 8vo , 2 50 

Steam-boiler Explosions in Theory and in Practice i2mo, 1 50 

Manual of Steam-boilers, Their Designs, Construction, and Operation. 8vo, 5 00 

Weisbach's Heat, Steam, and Steam-engines. (Du Bois.) 8vo, 5 00 

Whitham's Steam-engine Design 8vo, 5 00 

Wilson's Treatise on Steam-boilers. (Flather.) i6mo, 2 50 

Wood's Thermodynamics, Heat Motors, and Refrigerating Machines. . . .8vo, 4 00 



MECHANICS AND MACHINERY. 

Barr's Kinematics of Machinery 8vo, 2 50 

Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 

Chase's The Art of Pattern-making i2mo, 2 50 

Chordal.— Extracts from Letters i2mo, 2 00 

Church's Mechanics of Engineering 8vo, 6 00 

Notes and Examples in Mechanics 8vo, 2 00 

Compton's First Lessons in Metal-working nmo, 1 50 

Compton and De Groodt's The Speed Lathe nmo, 1 50 

Cromwell's Treatise on Toothed Gearing nmo, 1 50 

Treatise on Belts and Pulleys. nmo, 1 50 

Dana's Text-book of Elementary Mechanics for the Use of Colleges and 

Schools nmo, 1 5° 

Dingey's Machinery Pattern Making nmo, 2 00 

Dredge's Record of the Transportation Exhibits Building of the World's 

Columbian Exposition of 1893 4to, half morocco, 5 00 

Du Bois's Elementary Principles of Mechanics : 

Vol. I. — Kinematics 8vo, 

Vol. H.— Statics 8vo, 

Vol. III.— Kinetics 8vo, 

Mechanics of Engineering. Vol. I Small 4to, 

Vol. II Small 4to, 

Durley's Kinematics of Machines 8vo , 

Fitzgerald's Boston Machinist i6mo, 

Flather's Dynamometers, and the Measurement of Power nmo, 3 00 

Rope Driving nmo, 2 00 

Goss's Locomotive Sparks 8vo, 2 00 

Hall's Car Lubrication nmo, 1 00 

Holly's Art of Saw Filing i8mo 75 

* Johnson's Theoretical Mechanics nmo, 3 00 

Statics by Graphic and Algebraic Methods 8vo, 2 00 

Jones's Machine Design: 

Part I. — Kinematics of Machinery 8vo, 1 50 

Part H. — Form, Strength, and Proportions of Parts 8vo, 3 00 

Kerr's Power and Power Transmission 8vo, 2 00 

Lanza's Applied Mechanics 8vo, 7 50 

MacCord's Kinematics; or, Practical Mechanism 8vo, 5 00 

Velocity Diagrams 8vo, 1 50 

Maurer's Technical Mechanics. (In preparation.) 

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Merriman's Text-book on the Mechanics of Materials 8vo, 4 00 

* Michie's Elements of Analytical Mechanics 8vo, 4 00 

Reagan's Locomotives: Simple, Compound, and Electric nmo,- 2 50 

Reid's Course in Mechanical Drawing 8vo, 2 00 

Text-book of Mechanical Drawing and Elementary Machine Design . . 8vo, 3 00 

Richards's Compressed Air nmo, 1 50 

Robinson's Principles of Mechanism 8vo, 3 00 

Ryan, Norris, and Hoxie's Electrical Machinery. (In preparation.) 

Sinclair's Locomotive-engine Running and Management nmo, 2 00 

Smith's Press-working of Metals 8vo, 3 00 

Materials of Machines nmo, 1 00 

Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo, 3 00 

Thurston's Treatise on Friction and Lost Work in Machinery and Mill 

Work 8vo, 3 00 

Animal as a Machine and Prime Motor, and the Laws of Energetics. i2mo, 1 00 

Warren's Elements of Machine Construction and Drawing 8vo, 7 50 

Weisbach's Kinematics and the Power of Transmission. (Herrmann — 

Klein.) 8vo, 5 00 

Machinery of Transmission and Governors. (Herrmann — Klein. ).8vo, 5 00 

Wood's Elements of Analytical Mechanics 8vo, 3 00 

Principles of Elementary Mechanics nmo, 1 25 

Turbines 8vo, 2 50 

The World's Columbian Exposition of 1893 4to, 1 00 

METALLURGY. 

Egleston's Metallurgy of Silver, Gold, and Mercury: 

Vol. I.— Silver 8vo, 7 50 

Vol. II. — Gold and Mercury 8vo, 7 50 

** Iles's Lead-smelting. (Postage g cents additional.) nmo, 2 50 

Keep's Cast Iron 8vo, 2 50 

Kunhardt's Practice of Ore Dressing in Europe 8vo, 1 50 

Le Chatelier's High-temperature Measurements. ( Boudouard — Burgess.) . nmo, 3 00 

Metcalf's Steel. A Manual for Steel-users nmo, 2 00 

Smith's Materials of Machines nmo, 1 00 

Thurston's Materials of Engineering. In Three Parts 8vo, 8 00 

Part II. — Iron and Steel 8vo, 3 50 

Part III. — A Treatise on Brasses, Bronzes, and Other Alloys and their 

Constituents 8vo, 2 50 

Ulke's Modern Electrolytic Copper Refining 8vo, ?3 00 

MINERALOGY. 

Barringer's Description of Minerals of Commercial Value. Oblong, morocco, 2 50 

Boyd's Resources of Southwest Virginia 8vo, 3 00 

Map of Southwest Virginia Pocket-book form, 2 00 

Brush's Manual of Determinative Mineralogy. (Penfield.) 8vo, 4 00 

Chester's Catalogue of Minerals 8vo, paper, 1 00 

Cloth, 

Dictionary of the Names of Minerals 8vo, 

Dana's System of Mineralogy Large 8vo, half leather, 

First Appendix to Dana's New "System of Mineralogy.". . . Large 8vo, 

Text-book of Mineralogy 8vo, 

Minerals and How to Study Them nmo, 

Catalogue of American Localities of Minerals Large 8vo, 

Manual of Mineralogy and Petrography nmo, 

Egleston's Catalogue of Minerals and Synonyms 8vo, 

Hussak's The Determination of Rock-forming Minerals. (Smith.) Small 8vo, 

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* Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 

8vo, paper, 

Rosenbusch's Microscopical Physiography of the Rock-making Minerals. 

(Iddings.) 8vo, 

* Tillman's Text-book of Important Minerals and Docks 8vo, 

Williams's Manual of Lithology 8vo, 



MINING. 

Beard's Ventilation of Mines nmo, 2 50 

Boyd's Resources of Southwest Virginia 8vo, 3 00 

Map of Southwest Virginia Pocket-book form, 2 00 

* Drinker's Tunneling, Explosive Compounds, and Rock Drills. 

4to, half morocco, 25 00 

Eissler's Modern High Explosives 8vo, 4 00 

Fowler's Sewage Works Analyses nmo, 2 00 

Goodyear's Coal-mines of the Western Coast of the United States nmo, 2 50 

Ihlseng's Manual of Mining 8vo, 4 00 

** Iles's Lead-smelting. (Postage ox. additional.) nmo, 2 50 

Kunhardt's Practice of Ore Dressing in Europe 8vo, 1 50 

O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 00 

* Walke's Lectures on Explosives 8vo, 4 00 

Wilson's Cyanide Processes nmo, 1 50 

Chlorination Process nmo, 1 50 

Hydraulic and Placer Mining 12 no, 2 00 

Treatise on Practical and Theoretical Mine Ventilation 12 mo, 1 25 



SANITARY SCIENCE. 

Copeland's Manual of Bacteriology. (In preparation.) 

Folwell's Sewerage. (Designing, Construction, and Maintenance.) 8vo, 3 00 

Water-supply Engineering 8vo, 4 00 

Fuertes's Water and Public Health nmo, 1 50 

Water-filtration Works nmo, 2 50 

Gerhard's Guide to Sanitary House-inspection i6mo, 1 00 

Goodrich's Economical Disposal of Town's Refuse Demy 8vo, 3 50 

Hazen's Filtration of Public Water-supplies 8vo, 3 00 

Kiersted's Sewage Disposal nmo, 1 25 

Leach's The Inspection and Analysis of Food with Special Reference to State 

Control. {In preparation.) 
Mason's Water-supply. (Considered Principally from a Sanitary Stand- 
point.) 3d Edition, Rewritten 8 VOj 4 00 

Examination of Water. (Chemical and Bacteriological.) nmo, 1 25 

Merriman's Elements of Sanitary Engineering 8vo, 2 00 

Nichols's Water-supply. (Considered Mainly from a Chemical and Sanitary 

Standpoint.) (1883.) 8 V0) 2 50 

Ogden's Sewer Design nmo, 2 00 

* Price's Handbook on Sanitation nmo, 1 50 

Richards's Cost of Food. A Study in Dietaries nmo, 1 00 

Cost of Living as Modified by Sanitary Science nmo, 1 00 

Richards and Woodman's Air, Water, and Food from a Sanitary Stand- 
point 8vo, 2 00 

* Richards and Williams's The Dietary Computer 8vo, 1 50 

Rideal's Sewage and Bacterial Purification of Sewage 8vo, 3 50 

Turneaure and Russell's Public Water-supplies 8vo, 5 00 

Whipple's Microscopy of Drinking-water 8vo, 3 50 

Woodhull's Notes and_Military Hygiene i6mo, 1 50 

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MISCELLANEOUS. 

Barker's Deep-sea Soundings 8vo, 2 00 

Emmons's Geological Guide-book of the Rocky Mountain Excursion of the 

International Congress of Geologists Large 8vo, 1 50 

Fen-el's Popular Treatise on the Winds 8vo, 4 00 

Haines's American Railway Management i2mo, 2 50 

Mott's Composition, Digestibility, and Nutritive Value of Food. Mounted chart. 1 25 

Fallacy of the Present Theory of Sound i6mo, 1 00 

Ricketts's History of Rensselaer Polytechnic Institute, 1824-1894. Small 8vo, 3 00 

Rotherham's Emphasized New Testament Large 8vo, 2 00 

Steel's Treatise on the Diseases of the Dog 8vo, 3 50 

Totten's Important Question in Metrology 8vo, 2 50 

The World's Columbian Exposition of 1893 4to, 1 00 

Worcester and Atkinson. Small Hospitals, Establishment and Maintenance, 
and Suggestions for Hospital Architecture, with Plans for a Small 

Hospital i2mo, 1 25 

HEBREW AND CHALDEE TEXT-BOOKS. 

Green's Grammar of the Hebrew Language 8vo, 3 00 

Elementary Hebrew Grammar nmo, 1 25 

Hebrew Chrestomathy 8vo, 2 00 

Gesenius's Hebrew and Chaldee Lexicon to the Old Testament Scriptures. 

*■■ (Tregelles.) Small 4to, half morocco, 5 00 

Letteris's Hebrew Bible , 8vo, 2 25 

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